diff --git a/.env.example b/.env.example
index e24b118..d63e019 100644
--- a/.env.example
+++ b/.env.example
@@ -14,6 +14,7 @@ ASSOCIATION_NAME="Sportsclub XYZ"
 # Optional: Admin user (created/updated on container start via Release.seed_admin)
 # In production, set these so the first admin can log in. Change password without redeploy:
 #   bin/mv eval "Mv.Release.seed_admin()"  (with new ADMIN_PASSWORD or ADMIN_PASSWORD_FILE)
+# FORCE_SEEDS=true re-runs bootstrap seeds even when admin user exists (e.g. after changing roles/custom fields).
 # ADMIN_EMAIL=admin@example.com
 # ADMIN_PASSWORD=secure-password
 # ADMIN_PASSWORD_FILE=/run/secrets/admin_password
@@ -41,3 +42,15 @@ ASSOCIATION_NAME="Sportsclub XYZ"
 # VEREINFACHT_API_KEY=your-api-key
 # VEREINFACHT_CLUB_ID=2
 # VEREINFACHT_APP_URL=https://app.verein.visuel.dev
+
+# Optional: Mail / SMTP (transactional emails). If set, overrides Settings UI.
+# Export current UI settings to .env: mix mv.export_smtp_to_env
+# SMTP_HOST=smtp.example.com
+# SMTP_PORT=587
+# SMTP_USERNAME=user
+# SMTP_PASSWORD=secret
+# SMTP_PASSWORD_FILE=/run/secrets/smtp_password
+# SMTP_SSL=tls
+# SMTP_VERIFY_PEER=false
+# MAIL_FROM_EMAIL=noreply@example.com
+# MAIL_FROM_NAME=Mila
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 681169f..b94ce50 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,7 +5,19 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [1.1.1] - 2026-03-16
+
+### Added
+- **FORCE_SEEDS** – Environment variable. When set to `"true"`, bootstrap (and optionally dev) seeds are run even when the admin user already exists, so you can re-apply changed seed data (e.g. new roles or custom fields) without deleting the admin user.
+- **Improved OIDC-only mode** – Admin can enable “Only OIDC sign-in” in settings; when enabled, direct registration is disabled and sign-in page redirects to OIDC when configured.
+- **Success toast auto-dismiss** – Success flash messages (e.g. “Settings saved”) hide automatically after 5 seconds instead of requiring the user to close them.
+
+### Changed
+- **Seeds run only when needed** – Bootstrap and dev seeds are skipped on application start when the admin user already exists (`Mv.Release.bootstrap_seeds_applied?/0`). This avoids duplicate data and speeds up startup in dev and production after the first run. Set `FORCE_SEEDS=true` to override and re-run.
+- **Unauthenticated access** – Users who are not logged in are redirected to sign-in without showing a “no permission” message; the message is only shown to logged-in users who lack access.
+
+### Fixed
+- **SMTP configuration** – Repaired so that both port 587 (TLS/STARTTLS) and 465 (SSL) work correctly.
 
 ## [1.1.0] - 2026-03-13
 
diff --git a/CODE_GUIDELINES.md b/CODE_GUIDELINES.md
index 8d53484..f84c5ad 100644
--- a/CODE_GUIDELINES.md
+++ b/CODE_GUIDELINES.md
@@ -130,6 +130,8 @@ lib/
 │   ├── constants.ex       # Application constants (member_fields, custom_field_prefix, vereinfacht_required_member_fields)
 │   ├── application.ex     # OTP application
 │   ├── mailer.ex          # Email mailer
+│   ├── smtp/
+│   │   └── config_builder.ex  # SMTP adapter opts (TLS/sockopts); used by runtime.exs and Mailer
 │   ├── release.ex         # Release tasks
 │   ├── repo.ex            # Database repository
 │   ├── secrets.ex         # Secret management
@@ -282,13 +284,13 @@ end
 
 ### 1.2.1 Database Seeds
 
-Seeds are split into **bootstrap** and **dev**:
+Seeds are split into **bootstrap** and **dev**. They run on every start (e.g. `just run`, Docker entrypoint) but **exit early** if already applied so startup stays fast and no duplicate data is created.
 
-- **`priv/repo/seeds.exs`** – Entrypoint. Runs `seeds_bootstrap.exs` always; runs `seeds_dev.exs` only when `Mix.env()` is `:dev` or `:test`.
+- **`priv/repo/seeds.exs`** – Entrypoint. If the admin user (ADMIN_EMAIL or default) already exists, skips entirely (unless `FORCE_SEEDS=true`); otherwise runs `seeds_bootstrap.exs` and, in dev/test, `seeds_dev.exs`.
 - **`priv/repo/seeds_bootstrap.exs`** – Creates only data required for system startup: membership fee types, custom fields, roles, admin user, system user, global settings (including default membership fee type). No members, no groups. Used in all environments (dev, test, prod).
 - **`priv/repo/seeds_dev.exs`** – Creates 20 sample members, groups, and optional custom field values. Run only in dev and test.
 
-In production, running `mix run priv/repo/seeds.exs` executes only the bootstrap part (no dev seeds).
+In production, running `mix run priv/repo/seeds.exs` (or `Mv.Release.run_seeds/0`) executes only the bootstrap part when not yet applied (no dev seeds unless `RUN_DEV_SEEDS=true`). The “already applied” check uses `Mv.Release.bootstrap_seeds_applied?/0` (admin user exists). Set `FORCE_SEEDS=true` to re-run seeds even when already applied.
 
 ### 1.3 Domain-Driven Design
 
diff --git a/assets/js/app.js b/assets/js/app.js
index 87f2c25..4c7e3c5 100644
--- a/assets/js/app.js
+++ b/assets/js/app.js
@@ -113,6 +113,25 @@ Hooks.FocusRestore = {
   }
 }
 
+// FlashAutoDismiss: after a delay, clear the flash so the toast hides without user clicking X (e.g. success toasts)
+Hooks.FlashAutoDismiss = {
+  mounted() {
+    const ms = this.el.dataset.autoClearMs
+    if (!ms) return
+    const delay = parseInt(ms, 10)
+    if (delay > 0) {
+      this.timer = setTimeout(() => {
+        const key = this.el.dataset.clearFlashKey || "success"
+        this.pushEvent("lv:clear-flash", {key})
+      }, delay)
+    }
+  },
+
+  destroyed() {
+    if (this.timer) clearTimeout(this.timer)
+  }
+}
+
 // TabListKeydown hook: WCAG tab pattern — prevent default for ArrowLeft/ArrowRight so the server can handle tab switch (roving tabindex)
 Hooks.TabListKeydown = {
   mounted() {
diff --git a/config/runtime.exs b/config/runtime.exs
index 1c55f64..6a434fa 100644
--- a/config/runtime.exs
+++ b/config/runtime.exs
@@ -226,11 +226,7 @@ if config_env() == :prod do
   # SMTP configuration from environment variables (overrides base adapter in prod).
   # When SMTP_HOST is set, configure Swoosh to use the SMTP adapter at boot time.
   # If SMTP is configured only via Settings (Admin UI), the mailer builds the config
-  # per-send at runtime using Mv.Config.smtp_*() helpers.
-  #
-  # TLS/SSL options (tls_options, sockopts) are duplicated here and in Mv.Mailer.smtp_config/0
-  # because boot config must be set in this file; the Mailer uses the same logic for
-  # Settings-only config. Keep verify behaviour in sync (see SMTP_VERIFY_PEER below).
+  # per-send at runtime using Mv.Mailer.smtp_config/0 (which uses the same Mv.Smtp.ConfigBuilder).
   smtp_host_env = System.get_env("SMTP_HOST")
 
   if smtp_host_env && String.trim(smtp_host_env) != "" do
@@ -264,20 +260,14 @@ if config_env() == :prod do
     verify_mode = if smtp_verify_peer, do: :verify_peer, else: :verify_none
 
     smtp_opts =
-      [
-        adapter: Swoosh.Adapters.SMTP,
-        relay: String.trim(smtp_host_env),
+      Mv.Smtp.ConfigBuilder.build_opts(
+        host: String.trim(smtp_host_env),
         port: smtp_port_env,
         username: System.get_env("SMTP_USERNAME"),
         password: smtp_password_env,
-        ssl: smtp_ssl_mode == "ssl",
-        tls: if(smtp_ssl_mode == "tls", do: :always, else: :never),
-        auth: :always,
-        # tls_options: STARTTLS (587); sockopts: direct SSL (465).
-        tls_options: [verify: verify_mode],
-        sockopts: [verify: verify_mode]
-      ]
-      |> Enum.reject(fn {_k, v} -> is_nil(v) end)
+        ssl_mode: smtp_ssl_mode,
+        verify_mode: verify_mode
+      )
 
     config :mv, Mv.Mailer, smtp_opts
   end
diff --git a/docs/admin-bootstrap-and-oidc-role-sync.md b/docs/admin-bootstrap-and-oidc-role-sync.md
index 5e26c85..5413f91 100644
--- a/docs/admin-bootstrap-and-oidc-role-sync.md
+++ b/docs/admin-bootstrap-and-oidc-role-sync.md
@@ -2,7 +2,7 @@
 
 ## Overview
 
-- **Admin bootstrap:** In production, the Docker entrypoint runs migrate, then `Mv.Release.run_seeds/0` (bootstrap seeds; set `RUN_DEV_SEEDS=true` to also run dev seeds), then `seed_admin/0` from ENV, then the server. Password can be changed without redeploy via `bin/mv eval "Mv.Release.seed_admin()"`.
+- **Admin bootstrap:** In production, the Docker entrypoint runs migrate, then `Mv.Release.run_seeds/0` (skips if admin user already exists unless `FORCE_SEEDS=true`; set `RUN_DEV_SEEDS=true` to also run dev seeds), then `seed_admin/0` from ENV, then the server. Password can be changed without redeploy via `bin/mv eval "Mv.Release.seed_admin()"`.
 - **OIDC role sync:** Optional mapping from OIDC groups (e.g. from Authentik profile scope) to the Admin role. Users in the configured admin group get the Admin role on registration and on each sign-in.
 
 ## Admin Bootstrap (Part A)
@@ -10,13 +10,14 @@
 ### Environment Variables
 
 - `RUN_DEV_SEEDS` – If set to `"true"`, `run_seeds/0` also runs dev seeds (members, groups, sample data). Otherwise only bootstrap seeds run.
+- `FORCE_SEEDS` – If set to `"true"`, seeds are run even when the admin user already exists (e.g. after changing bootstrap data such as roles or custom fields). Otherwise seeds are skipped when bootstrap was already applied.
 - `ADMIN_EMAIL` – Email of the admin user to create/update. If unset, seed_admin/0 does nothing.
 - `ADMIN_PASSWORD` – Password for the admin user. If unset (and no file), no new user is created; if a user with ADMIN_EMAIL already exists (e.g. OIDC-only), their role is set to Admin (no password change).
 - `ADMIN_PASSWORD_FILE` – Path to a file containing the password (e.g. Docker secret).
 
 ### Release Tasks
 
-- `Mv.Release.run_seeds/0` – Runs bootstrap seeds (fee types, custom fields, roles, settings). If `RUN_DEV_SEEDS` env is `"true"`, also runs dev seeds (members, groups, sample data). Idempotent.
+- `Mv.Release.run_seeds/0` – If the admin user already exists (bootstrap already applied), skips unless `FORCE_SEEDS=true`; otherwise runs bootstrap seeds (fee types, custom fields, roles, settings). If `RUN_DEV_SEEDS` env is `"true"`, also runs dev seeds (members, groups, sample data). Safe to call on every start.
 - `Mv.Release.seed_admin/0` – Reads ADMIN_EMAIL and password from ADMIN_PASSWORD or ADMIN_PASSWORD_FILE. If both email and password are set: creates or updates the user with the Admin role. If only ADMIN_EMAIL is set: sets the Admin role on an existing user with that email (for OIDC-only admins); does not create a user. Idempotent.
 
 ### Entrypoint
@@ -38,6 +39,7 @@
 ### Sign-in page (OIDC-only mode)
 
 - `OIDC_ONLY` (or Settings → OIDC → "Only OIDC sign-in") – When set to true/1/yes and OIDC is configured, the sign-in page shows only the Single Sign-On button (password login is hidden). ENV takes precedence over Settings.
+- **Redirect loop fix:** After an OIDC failure (e.g. provider down), the app redirects to `/sign-in?oidc_failed=1`. The plug `OidcOnlySignInRedirect` does not redirect that request back to OIDC, so the sign-in page is shown with the error (no endless redirect).
 
 ### Sync Logic
 
diff --git a/docs/feature-roadmap.md b/docs/feature-roadmap.md
index 6383660..2ec15a5 100644
--- a/docs/feature-roadmap.md
+++ b/docs/feature-roadmap.md
@@ -49,6 +49,11 @@
 - ✅ **Page-level authorization** - LiveView page access control
 - ✅ **System role protection** - Critical roles cannot be deleted
 
+**Planned: OIDC-only mode (TDD, tests first):**
+- Admin Settings: When OIDC-only is enabled, disable "Allow direct registration" toggle and show hint (tests in `GlobalSettingsLiveTest`).
+- Backend: Reject password sign-in and `register_with_password` when OIDC-only (tests in `AuthControllerTest`, `Accounts`).
+- GET `/sign-in` redirect to OIDC when OIDC-only and OIDC configured (tests in `AuthControllerTest`). Implementation to follow after tests.
+
 **Missing Features:**
 - ❌ Password reset flow
 - ❌ Email verification
diff --git a/docs/smtp-configuration-concept.md b/docs/smtp-configuration-concept.md
index 8832b5e..13b0d17 100644
--- a/docs/smtp-configuration-concept.md
+++ b/docs/smtp-configuration-concept.md
@@ -105,7 +105,7 @@ By default, TLS certificate verification is relaxed (`verify_none`) so self-sign
 - **ENV (prod):** Set `SMTP_VERIFY_PEER=true` (or `1`/`yes`) when configuring SMTP via environment variables in `config/runtime.exs`. This sets `config :mv, :smtp_verify_peer` and is used for both boot-time and per-send config.
 - **Default:** `false` (verify_none) for backward compatibility and internal/self-signed certs.
 
-Both `tls_options` (STARTTLS, port 587) and `sockopts` (direct SSL, port 465) use the same verify mode. The logic is duplicated in `config/runtime.exs` (boot) and `Mv.Mailer.smtp_config/0` (Settings-only); keep in sync.
+Verify mode is set in `tls_options` for port 587 (STARTTLS). For port 465 (implicit SSL), the initial connection is `ssl:connect`, so we also pass `sockopts: [verify: verify_mode]` so the SSL handshake uses the same mode. For 587 we must not pass `verify` in sockopts—gen_tcp is used first and rejects it (ArgumentError). The logic lives in `Mv.Smtp.ConfigBuilder.build_opts/1` (single source of truth), used by `config/runtime.exs` (boot) and `Mv.Mailer.smtp_config/0` (Settings-only).
 
 ---
 
@@ -117,7 +117,7 @@ Both `tls_options` (STARTTLS, port 587) and `sockopts` (direct SSL, port 465) us
 - [x] Password from file: `SMTP_PASSWORD_FILE` supported in `runtime.exs`.
 - [x] Mailer: Swoosh SMTP adapter configured from merged ENV + Settings when SMTP is configured.
 - [x] Per-request SMTP config via `Mv.Mailer.smtp_config/0` for Settings-only scenarios.
-- [x] TLS certificate validation relaxed for OTP 27 (tls_options + sockopts).
+- [x] TLS certificate validation relaxed for OTP 27 (tls_options for 587; sockopts with verify only for 465).
 - [x] Prod warning: clear message in Settings when SMTP is not configured.
 - [x] Test email: form with recipient field, translatable content, classified success/error messages.
 - [x] Join confirmation email: uses `Mailer.smtp_config/0` (same as test mail); on failure returns `{:error, :email_delivery_failed}`, error shown in JoinLive, logged for admin.
diff --git a/lib/accounts/user.ex b/lib/accounts/user.ex
index 29a2d4b..0127796 100644
--- a/lib/accounts/user.ex
+++ b/lib/accounts/user.ex
@@ -362,6 +362,12 @@ defmodule Mv.Accounts.User do
   # Authorization Policies
   # Order matters: Most specific policies first, then general permission check
   policies do
+    # When OIDC-only is active, password sign-in is forbidden (SSO only).
+    policy action(:sign_in_with_password) do
+      forbid_if Mv.Authorization.Checks.OidcOnlyActive
+      authorize_if always()
+    end
+
     # AshAuthentication bypass (registration/login without actor)
     bypass AshAuthentication.Checks.AshAuthenticationInteraction do
       description "Allow AshAuthentication internal operations (registration, login)"
@@ -409,6 +415,10 @@ defmodule Mv.Accounts.User do
     validate {Mv.Accounts.User.Validations.RegistrationEnabled, []},
       where: [action_is(:register_with_password)]
 
+    # Block password registration when OIDC-only mode is active
+    validate {Mv.Accounts.User.Validations.OidcOnlyBlocksPasswordRegistration, []},
+      where: [action_is(:register_with_password)]
+
     # Email uniqueness check for all actions that change the email attribute
     # Validates that user email is not already used by another (unlinked) member
     validate Mv.Accounts.User.Validations.EmailNotUsedByOtherMember
diff --git a/lib/accounts/user/validations/oidc_only_blocks_password_registration.ex b/lib/accounts/user/validations/oidc_only_blocks_password_registration.ex
new file mode 100644
index 0000000..e4d9a35
--- /dev/null
+++ b/lib/accounts/user/validations/oidc_only_blocks_password_registration.ex
@@ -0,0 +1,27 @@
+defmodule Mv.Accounts.User.Validations.OidcOnlyBlocksPasswordRegistration do
+  @moduledoc """
+  Validation that blocks direct registration (register_with_password) when
+  OIDC-only mode is active. In OIDC-only mode, sign-in and registration are
+  only allowed via OIDC (SSO).
+  """
+  use Ash.Resource.Validation
+
+  @impl true
+  def init(opts), do: {:ok, opts}
+
+  @impl true
+  def validate(_changeset, _opts, _context) do
+    if Mv.Config.oidc_only?() do
+      {:error,
+       field: :base,
+       message:
+         Gettext.dgettext(
+           MvWeb.Gettext,
+           "default",
+           "Registration with password is disabled when only OIDC sign-in is active."
+         )}
+    else
+      :ok
+    end
+  end
+end
diff --git a/lib/mv/authorization/checks/oidc_only_active.ex b/lib/mv/authorization/checks/oidc_only_active.ex
new file mode 100644
index 0000000..8d56ca1
--- /dev/null
+++ b/lib/mv/authorization/checks/oidc_only_active.ex
@@ -0,0 +1,16 @@
+defmodule Mv.Authorization.Checks.OidcOnlyActive do
+  @moduledoc """
+  Policy check: true when OIDC-only mode is active (Config.oidc_only?()).
+
+  Used to forbid password sign-in when only OIDC (SSO) sign-in is allowed.
+  """
+  use Ash.Policy.SimpleCheck
+
+  alias Mv.Config
+
+  @impl true
+  def describe(_opts), do: "OIDC-only mode is active"
+
+  @impl true
+  def match?(_actor, _context, _opts), do: Config.oidc_only?()
+end
diff --git a/lib/mv/mailer.ex b/lib/mv/mailer.ex
index e5ac4e9..41a77cd 100644
--- a/lib/mv/mailer.ex
+++ b/lib/mv/mailer.ex
@@ -31,6 +31,7 @@ defmodule Mv.Mailer do
   import Swoosh.Email
   use Gettext, backend: MvWeb.Gettext, otp_app: :mv
 
+  alias Mv.Smtp.ConfigBuilder
   require Logger
 
   # Simple format check for test-email recipient only (e.g. allows a@b.c). Not for strict RFC validation.
@@ -100,31 +101,19 @@ defmodule Mv.Mailer do
   @spec smtp_config() :: keyword()
   def smtp_config do
     if Mv.Config.smtp_configured?() and not boot_smtp_configured?() do
-      host = Mv.Config.smtp_host()
-      port = Mv.Config.smtp_port() || 587
-      username = Mv.Config.smtp_username()
-      password = Mv.Config.smtp_password()
-      ssl_mode = Mv.Config.smtp_ssl() || "tls"
-
       verify_mode =
         if Application.get_env(:mv, :smtp_verify_peer, false),
           do: :verify_peer,
           else: :verify_none
 
-      [
-        adapter: Swoosh.Adapters.SMTP,
-        relay: host,
-        port: port,
-        ssl: ssl_mode == "ssl",
-        tls: if(ssl_mode == "tls", do: :always, else: :never),
-        auth: :always,
-        username: username,
-        password: password,
-        # tls_options: STARTTLS (587); sockopts: direct SSL (465). Verify from :smtp_verify_peer (ENV SMTP_VERIFY_PEER).
-        tls_options: [verify: verify_mode],
-        sockopts: [verify: verify_mode]
-      ]
-      |> Enum.reject(fn {_k, v} -> is_nil(v) end)
+      ConfigBuilder.build_opts(
+        host: Mv.Config.smtp_host(),
+        port: Mv.Config.smtp_port() || 587,
+        username: Mv.Config.smtp_username(),
+        password: Mv.Config.smtp_password(),
+        ssl_mode: Mv.Config.smtp_ssl() || "tls",
+        verify_mode: verify_mode
+      )
     else
       []
     end
diff --git a/lib/mv/release.ex b/lib/mv/release.ex
index 00dcadf..116b276 100644
--- a/lib/mv/release.ex
+++ b/lib/mv/release.ex
@@ -6,8 +6,8 @@ defmodule Mv.Release do
   ## Tasks
 
   - `migrate/0` - Runs all pending Ecto migrations.
-  - `run_seeds/0` - Runs bootstrap seeds (fee types, custom fields, roles, settings).
-    In production, set `RUN_DEV_SEEDS=true` to also run dev seeds (members, groups, sample data).
+  - `bootstrap_seeds_applied?/0` - Returns whether bootstrap was already applied (admin user exists). Used to skip re-running seeds.
+  - `run_seeds/0` - If bootstrap already applied, skips; otherwise runs bootstrap seeds (fee types, custom fields, roles, settings). Set `FORCE_SEEDS=true` to re-run seeds even when already applied. In production, set `RUN_DEV_SEEDS=true` to also run dev seeds (members, groups, sample data).
   - `seed_admin/0` - Ensures an admin user exists from ENV (ADMIN_EMAIL, ADMIN_PASSWORD
     or ADMIN_PASSWORD_FILE). Idempotent; can be run on every deployment or via shell
     to update the admin password without redeploying.
@@ -19,6 +19,7 @@ defmodule Mv.Release do
   alias Mv.Authorization.Role
 
   require Ash.Query
+  require Logger
 
   def migrate do
     load_app()
@@ -28,13 +29,37 @@ defmodule Mv.Release do
     end
   end
 
+  @doc """
+  Returns whether bootstrap seeds have already been applied (admin user exists).
+
+  We check for the admin user (from ADMIN_EMAIL or default), not the Admin role,
+  because migrations may create the Admin role for the system actor. Only seeds
+  create the admin (login) user. Used to skip re-running seeds on subsequent starts.
+  Call only when the application is already started.
+  """
+  def bootstrap_seeds_applied? do
+    admin_email = get_env("ADMIN_EMAIL", "admin@localhost")
+
+    case User
+         |> Ash.Query.filter(email == ^admin_email)
+         |> Ash.read_one(authorize?: false, domain: Mv.Accounts) do
+      {:ok, %User{}} -> true
+      _ -> false
+    end
+  rescue
+    e ->
+      Logger.warning("Could not check seed status (#{inspect(e)}), assuming not applied.")
+      false
+  end
+
   @doc """
   Runs seed scripts so the database has required bootstrap data (and optionally dev data).
 
-  - Always runs bootstrap seeds (fee types, custom fields, roles, system user, settings).
-  - If `RUN_DEV_SEEDS` env is set to `"true"`, also runs dev seeds (members, groups, sample data).
+  - Skips if bootstrap was already applied (admin user exists); set `FORCE_SEEDS=true` to override and re-run.
+  - If `RUN_DEV_SEEDS` env is set to `"true"`, also runs dev seeds (members, groups, sample data)
+    when bootstrap is run.
 
-  Uses paths from the application's priv dir so it works in releases (no Mix). Idempotent.
+  Uses paths from the application's priv dir so it works in releases (no Mix).
   """
   def run_seeds do
     case Application.ensure_all_started(@app) do
@@ -42,23 +67,27 @@ defmodule Mv.Release do
       {:error, {app, reason}} -> raise "Failed to start #{inspect(app)}: #{inspect(reason)}"
     end
 
-    priv = :code.priv_dir(@app)
-    bootstrap_path = Path.join(priv, "repo/seeds_bootstrap.exs")
-    dev_path = Path.join(priv, "repo/seeds_dev.exs")
+    if bootstrap_seeds_applied?() and System.get_env("FORCE_SEEDS") != "true" do
+      IO.puts("Seeds already applied. Skipping. (Set FORCE_SEEDS=true to override)")
+    else
+      priv = :code.priv_dir(@app)
+      bootstrap_path = Path.join(priv, "repo/seeds_bootstrap.exs")
+      dev_path = Path.join(priv, "repo/seeds_dev.exs")
 
-    prev = Code.compiler_options()
-    Code.compiler_options(ignore_module_conflict: true)
+      prev = Code.compiler_options()
+      Code.compiler_options(ignore_module_conflict: true)
 
-    try do
-      Code.eval_file(bootstrap_path)
-      IO.puts("✅ Bootstrap seeds completed.")
+      try do
+        Code.eval_file(bootstrap_path)
+        IO.puts("✅ Bootstrap seeds completed.")
 
-      if System.get_env("RUN_DEV_SEEDS") == "true" do
-        Code.eval_file(dev_path)
-        IO.puts("✅ Dev seeds completed.")
+        if System.get_env("RUN_DEV_SEEDS") == "true" do
+          Code.eval_file(dev_path)
+          IO.puts("✅ Dev seeds completed.")
+        end
+      after
+        Code.compiler_options(prev)
       end
-    after
-      Code.compiler_options(prev)
     end
   end
 
diff --git a/lib/mv/smtp/config_builder.ex b/lib/mv/smtp/config_builder.ex
new file mode 100644
index 0000000..5018dff
--- /dev/null
+++ b/lib/mv/smtp/config_builder.ex
@@ -0,0 +1,58 @@
+defmodule Mv.Smtp.ConfigBuilder do
+  @moduledoc """
+  Builds Swoosh/gen_smtp SMTP adapter options from connection parameters.
+
+  Single source of truth for TLS/sockopts logic (port 587 vs 465):
+  - Port 587 (STARTTLS): `gen_tcp` is used first; `sockopts` must NOT contain `:verify`.
+  - Port 465 (implicit SSL): initial connection is `ssl:connect`; `sockopts` must contain `:verify`.
+
+  Used by `config/runtime.exs` (boot-time ENV) and `Mv.Mailer.smtp_config/0` (Settings-only).
+  """
+
+  @doc """
+  Builds the keyword list of Swoosh SMTP adapter options.
+
+  Options (keyword list):
+  - `:host` (required) — relay hostname
+  - `:port` (required) — port number (e.g. 587 or 465)
+  - `:ssl_mode` (required) — `"tls"` or `"ssl"`
+  - `:verify_mode` (required) — `:verify_peer` or `:verify_none`
+  - `:username` (optional)
+  - `:password` (optional)
+
+  Nil values are stripped from the result.
+  """
+  @spec build_opts(keyword()) :: keyword()
+  def build_opts(opts) do
+    host = Keyword.fetch!(opts, :host)
+    port = Keyword.fetch!(opts, :port)
+    username = Keyword.get(opts, :username)
+    password = Keyword.get(opts, :password)
+    ssl_mode = Keyword.fetch!(opts, :ssl_mode)
+    verify_mode = Keyword.fetch!(opts, :verify_mode)
+
+    base_opts = [
+      adapter: Swoosh.Adapters.SMTP,
+      relay: host,
+      port: port,
+      username: username,
+      password: password,
+      ssl: ssl_mode == "ssl",
+      tls: if(ssl_mode == "tls", do: :always, else: :never),
+      auth: :always,
+      # tls_options: used for STARTTLS (587). For 465, gen_smtp uses sockopts for initial ssl:connect.
+      tls_options: [verify: verify_mode]
+    ]
+
+    # Port 465: initial connection is ssl:connect; pass verify in sockopts.
+    # Port 587: initial connection is gen_tcp; sockopts must NOT contain verify (gen_tcp rejects it).
+    opts =
+      if ssl_mode == "ssl" do
+        Keyword.put(base_opts, :sockopts, verify: verify_mode)
+      else
+        base_opts
+      end
+
+    Enum.reject(opts, fn {_k, v} -> is_nil(v) end)
+  end
+end
diff --git a/lib/mv_web/components/core_components.ex b/lib/mv_web/components/core_components.ex
index 8c58c32..b5bd763 100644
--- a/lib/mv_web/components/core_components.ex
+++ b/lib/mv_web/components/core_components.ex
@@ -63,6 +63,11 @@ defmodule MvWeb.CoreComponents do
     values: [:info, :error, :success, :warning],
     doc: "used for styling and flash lookup"
 
+  attr :auto_clear_ms, :integer,
+    default: nil,
+    doc:
+      "when set, flash is auto-dismissed after this many milliseconds (e.g. 5000 for success toasts)"
+
   attr :rest, :global, doc: "the arbitrary HTML attributes to add to the flash container"
 
   slot :inner_block, doc: "the optional inner block that renders the flash message"
@@ -74,6 +79,9 @@ defmodule MvWeb.CoreComponents do
     <div
       :if={msg = render_slot(@inner_block) || Phoenix.Flash.get(@flash, @kind)}
       id={@id}
+      phx-hook={@auto_clear_ms && "FlashAutoDismiss"}
+      data-auto-clear-ms={@auto_clear_ms}
+      data-clear-flash-key={@auto_clear_ms && @kind}
       phx-click={JS.push("lv:clear-flash", value: %{key: @kind}) |> hide("##{@id}")}
       role="alert"
       class="pointer-events-auto"
diff --git a/lib/mv_web/components/layouts.ex b/lib/mv_web/components/layouts.ex
index 5a96001..54f589d 100644
--- a/lib/mv_web/components/layouts.ex
+++ b/lib/mv_web/components/layouts.ex
@@ -265,7 +265,7 @@ defmodule MvWeb.Layouts do
       aria-live="polite"
       class="z-50 toast toast-bottom toast-end flex flex-col gap-2 pointer-events-none"
     >
-      <.flash kind={:success} flash={@flash} />
+      <.flash kind={:success} flash={@flash} auto_clear_ms={5000} />
       <.flash kind={:warning} flash={@flash} />
       <.flash kind={:info} flash={@flash} />
       <.flash kind={:error} flash={@flash} />
diff --git a/lib/mv_web/components/layouts/root.html.heex b/lib/mv_web/components/layouts/root.html.heex
index 5419b73..bb900aa 100644
--- a/lib/mv_web/components/layouts/root.html.heex
+++ b/lib/mv_web/components/layouts/root.html.heex
@@ -74,7 +74,7 @@
       aria-live="polite"
       class="z-50 flex flex-col gap-2 toast toast-bottom toast-end"
     >
-      <.flash id="flash-success-root" kind={:success} flash={@flash} />
+      <.flash id="flash-success-root" kind={:success} flash={@flash} auto_clear_ms={5000} />
       <.flash id="flash-warning-root" kind={:warning} flash={@flash} />
       <.flash id="flash-info-root" kind={:info} flash={@flash} />
       <.flash id="flash-error-root" kind={:error} flash={@flash} />
diff --git a/lib/mv_web/controllers/auth_controller.ex b/lib/mv_web/controllers/auth_controller.ex
index 20a76f5..adde4e8 100644
--- a/lib/mv_web/controllers/auth_controller.ex
+++ b/lib/mv_web/controllers/auth_controller.ex
@@ -15,8 +15,23 @@ defmodule MvWeb.AuthController do
   use AshAuthentication.Phoenix.Controller
 
   alias Mv.Accounts.User.Errors.PasswordVerificationRequired
+  alias Mv.Config
 
-  def success(conn, activity, user, _token) do
+  def success(conn, {:password, :sign_in} = _activity, user, token) do
+    if Config.oidc_only?() do
+      conn
+      |> put_flash(:error, gettext("Only sign-in via Single Sign-On (SSO) is allowed."))
+      |> redirect(to: sign_in_path_after_oidc_failure())
+    else
+      success_continue(conn, {:password, :sign_in}, user, token)
+    end
+  end
+
+  def success(conn, activity, user, token) do
+    success_continue(conn, activity, user, token)
+  end
+
+  defp success_continue(conn, activity, user, _token) do
     return_to = get_session(conn, :return_to) || ~p"/"
 
     message =
@@ -134,7 +149,7 @@ defmodule MvWeb.AuthController do
       _ ->
         conn
         |> put_flash(:error, gettext("Unable to authenticate with OIDC. Please try again."))
-        |> redirect(to: ~p"/sign-in")
+        |> redirect(to: sign_in_path_after_oidc_failure())
     end
   end
 
@@ -148,7 +163,7 @@ defmodule MvWeb.AuthController do
       :error,
       gettext("The authentication server is currently unavailable. Please try again later.")
     )
-    |> redirect(to: ~p"/sign-in")
+    |> redirect(to: sign_in_path_after_oidc_failure())
   end
 
   # Handle Assent invalid response errors (configuration or malformed responses)
@@ -161,7 +176,7 @@ defmodule MvWeb.AuthController do
       :error,
       gettext("Authentication configuration error. Please contact the administrator.")
     )
-    |> redirect(to: ~p"/sign-in")
+    |> redirect(to: sign_in_path_after_oidc_failure())
   end
 
   # Catch-all clause for any other error types
@@ -171,7 +186,7 @@ defmodule MvWeb.AuthController do
 
     conn
     |> put_flash(:error, gettext("Unable to authenticate with OIDC. Please try again."))
-    |> redirect(to: ~p"/sign-in")
+    |> redirect(to: sign_in_path_after_oidc_failure())
   end
 
   # Handle generic AuthenticationFailed errors
@@ -211,10 +226,14 @@ defmodule MvWeb.AuthController do
 
         conn
         |> put_flash(:error, error_message)
-        |> redirect(to: ~p"/sign-in")
+        |> redirect(to: sign_in_path_after_oidc_failure())
     end
   end
 
+  # Path used when redirecting to sign-in after an OIDC failure. The query param tells
+  # OidcOnlySignInRedirect to show the sign-in page instead of redirecting back to OIDC (avoids loop).
+  defp sign_in_path_after_oidc_failure, do: "/sign-in?oidc_failed=1"
+
   # Extract meaningful error message from Ash errors
   defp extract_meaningful_error_message(errors) do
     # Look for specific error messages in InvalidAttribute errors
diff --git a/lib/mv_web/live/global_settings_live.ex b/lib/mv_web/live/global_settings_live.ex
index f69b947..cb57631 100644
--- a/lib/mv_web/live/global_settings_live.ex
+++ b/lib/mv_web/live/global_settings_live.ex
@@ -19,6 +19,7 @@ defmodule MvWeb.GlobalSettingsLive do
   ## Events
   - `validate` / `save` - Club settings form
   - `toggle_registration_enabled` - Enable/disable direct registration (/register)
+  - `toggle_oidc_only` - Enable/disable OIDC-only sign-in (immediate, outside OIDC form)
   - `toggle_join_form_enabled` - Enable/disable the join form
   - `add_join_form_field` / `remove_join_form_field` - Manage join form fields
   - `toggle_join_form_field_required` - Toggle required flag per field
@@ -80,6 +81,7 @@ defmodule MvWeb.GlobalSettingsLive do
       |> assign(:oidc_admin_group_name_env_set, Mv.Config.oidc_admin_group_name_env_set?())
       |> assign(:oidc_groups_claim_env_set, Mv.Config.oidc_groups_claim_env_set?())
       |> assign(:oidc_only_env_set, Mv.Config.oidc_only_env_set?())
+      |> assign(:oidc_only, Mv.Config.oidc_only?())
       |> assign(:oidc_configured, Mv.Config.oidc_configured?())
       |> assign(:oidc_client_secret_set, Mv.Config.oidc_client_secret_set?())
       |> assign(:registration_enabled, settings.registration_enabled != false)
@@ -625,11 +627,30 @@ defmodule MvWeb.GlobalSettingsLive do
               class="checkbox checkbox-sm"
               checked={@registration_enabled}
               phx-click="toggle_registration_enabled"
+              disabled={@oidc_only}
               aria-label={gettext("Allow direct registration (/register)")}
             />
-            <label for="registration-enabled-checkbox" class="cursor-pointer font-medium">
+            <label
+              for="registration-enabled-checkbox"
+              class={
+                if @oidc_only, do: "cursor-not-allowed opacity-70", else: "cursor-pointer font-medium"
+              }
+            >
               {gettext("Allow direct registration (/register)")}
             </label>
+            <%= if @oidc_only do %>
+              <.tooltip
+                content={gettext("Only OIDC sign-in is active. This option is disabled.")}
+                position="top"
+              >
+                <span
+                  data-testid="oidc-only-registration-hint"
+                  class="cursor-help text-base-content/70"
+                >
+                  ⓘ
+                </span>
+              </.tooltip>
+            <% end %>
           </div>
 
           <h3 class="font-medium mb-3">{gettext("OIDC (Single Sign-On)")}</h3>
@@ -638,6 +659,38 @@ defmodule MvWeb.GlobalSettingsLive do
               {gettext("Some values are set via environment variables. Those fields are read-only.")}
             </p>
           <% end %>
+          <div class="flex items-center gap-3 mb-4">
+            <input
+              type="checkbox"
+              id="oidc-only-checkbox"
+              data-testid="oidc-only-checkbox"
+              class="checkbox checkbox-sm"
+              checked={@oidc_only}
+              phx-click="toggle_oidc_only"
+              disabled={@oidc_only_env_set or not @oidc_configured}
+              aria-label={gettext("Only OIDC sign-in (hide password login)")}
+            />
+            <label
+              for="oidc-only-checkbox"
+              class={
+                if @oidc_only_env_set or not @oidc_configured,
+                  do: "cursor-not-allowed opacity-70",
+                  else: "cursor-pointer font-medium"
+              }
+            >
+              {if @oidc_only_env_set do
+                gettext("Only OIDC sign-in (hide password login)") <>
+                  " (" <> gettext("From OIDC_ONLY") <> ")"
+              else
+                gettext("Only OIDC sign-in (hide password login)")
+              end}
+            </label>
+          </div>
+          <p class="label-text-alt text-base-content/70 mb-4">
+            {gettext(
+              "When enabled and OIDC is configured, the sign-in page shows only the Single Sign-On button."
+            )}
+          </p>
           <.form for={@form} id="oidc-form" phx-change="validate" phx-submit="save">
             <div class="grid gap-4">
               <.input
@@ -744,27 +797,6 @@ defmodule MvWeb.GlobalSettingsLive do
                   )
                 }
               />
-              <div class="form-control">
-                <.input
-                  field={@form[:oidc_only]}
-                  type="checkbox"
-                  class="checkbox checkbox-sm"
-                  disabled={@oidc_only_env_set or not @oidc_configured}
-                  label={
-                    if @oidc_only_env_set do
-                      gettext("Only OIDC sign-in (hide password login)") <>
-                        " (" <> gettext("From OIDC_ONLY") <> ")"
-                    else
-                      gettext("Only OIDC sign-in (hide password login)")
-                    end
-                  }
-                />
-                <p class="label-text-alt text-base-content/70 mt-1">
-                  {gettext(
-                    "When enabled and OIDC is configured, the sign-in page shows only the Single Sign-On button."
-                  )}
-                </p>
-              </div>
             </div>
             <.button
               :if={
@@ -868,18 +900,19 @@ defmodule MvWeb.GlobalSettingsLive do
     saves_vereinfacht = vereinfacht_params?(setting_params_clean)
 
     case MvWeb.LiveHelpers.submit_form(socket.assigns.form, setting_params_clean, actor) do
-      {:ok, _updated_settings} ->
-        {:ok, fresh_settings} = Membership.get_settings()
-
+      {:ok, updated_settings} ->
+        # Use the returned record for the form so saved values show immediately;
+        # get_settings() can return cached data without the new attribute until reload.
         test_result =
           if saves_vereinfacht, do: Mv.Vereinfacht.test_connection(), else: nil
 
         socket =
           socket
-          |> assign(:settings, fresh_settings)
-          |> assign(:registration_enabled, fresh_settings.registration_enabled != false)
-          |> assign(:vereinfacht_api_key_set, present?(fresh_settings.vereinfacht_api_key))
+          |> assign(:settings, updated_settings)
+          |> assign(:registration_enabled, updated_settings.registration_enabled != false)
+          |> assign(:vereinfacht_api_key_set, present?(updated_settings.vereinfacht_api_key))
           |> assign(:oidc_client_secret_set, Mv.Config.oidc_client_secret_set?())
+          |> assign(:oidc_only, Mv.Config.oidc_only?())
           |> assign(:oidc_configured, Mv.Config.oidc_configured?())
           |> assign(:smtp_configured, Mv.Config.smtp_configured?())
           |> assign(:smtp_password_set, present?(Mv.Config.smtp_password()))
@@ -916,19 +949,53 @@ defmodule MvWeb.GlobalSettingsLive do
 
   @impl true
   def handle_event("toggle_registration_enabled", _params, socket) do
-    settings = socket.assigns.settings
-    new_value = not socket.assigns.registration_enabled
+    if Mv.Config.oidc_only?() do
+      {:noreply, socket}
+    else
+      settings = socket.assigns.settings
+      new_value = not socket.assigns.registration_enabled
 
-    case Membership.update_settings(settings, %{registration_enabled: new_value}) do
-      {:ok, updated_settings} ->
-        {:noreply,
-         socket
-         |> assign(:settings, updated_settings)
-         |> assign(:registration_enabled, updated_settings.registration_enabled != false)
-         |> assign_form()}
+      case Membership.update_settings(settings, %{registration_enabled: new_value}) do
+        {:ok, updated_settings} ->
+          {:noreply,
+           socket
+           |> assign(:settings, updated_settings)
+           |> assign(:registration_enabled, updated_settings.registration_enabled != false)
+           |> assign_form()}
 
-      {:error, _} ->
-        {:noreply, put_flash(socket, :error, gettext("Failed to update setting."))}
+        {:error, _} ->
+          {:noreply, put_flash(socket, :error, gettext("Failed to update setting."))}
+      end
+    end
+  end
+
+  @impl true
+  def handle_event("toggle_oidc_only", _params, socket) do
+    if socket.assigns.oidc_only_env_set do
+      {:noreply, socket}
+    else
+      settings = socket.assigns.settings
+      new_value = not socket.assigns.oidc_only
+
+      # When enabling OIDC-only, also disable direct registration; when disabling, only change oidc_only.
+      params =
+        if new_value,
+          do: %{oidc_only: true, registration_enabled: false},
+          else: %{oidc_only: false}
+
+      case Membership.update_settings(settings, params) do
+        {:ok, updated_settings} ->
+          {:noreply,
+           socket
+           |> assign(:settings, updated_settings)
+           |> assign(:oidc_only, updated_settings.oidc_only == true)
+           |> assign(:registration_enabled, updated_settings.registration_enabled != false)
+           |> assign_form()
+           |> put_flash(:success, gettext("Settings updated successfully"))}
+
+        {:error, _} ->
+          {:noreply, put_flash(socket, :error, gettext("Failed to update setting."))}
+      end
     end
   end
 
diff --git a/lib/mv_web/live_helpers.ex b/lib/mv_web/live_helpers.ex
index 38a0157..4206aa6 100644
--- a/lib/mv_web/live_helpers.ex
+++ b/lib/mv_web/live_helpers.ex
@@ -74,7 +74,7 @@ defmodule MvWeb.LiveHelpers do
 
         socket =
           socket
-          |> Phoenix.LiveView.put_flash(:error, "You don't have permission to access this page.")
+          |> maybe_put_access_denied_flash(user)
           |> Phoenix.LiveView.push_navigate(to: redirect_to)
 
         {:halt, socket}
@@ -82,6 +82,13 @@ defmodule MvWeb.LiveHelpers do
     end
   end
 
+  # Only show "no permission" when user is logged in; unauthenticated users are redirected to sign-in without flash.
+  defp maybe_put_access_denied_flash(socket, nil), do: socket
+
+  defp maybe_put_access_denied_flash(socket, _user) do
+    Phoenix.LiveView.put_flash(socket, :error, "You don't have permission to access this page.")
+  end
+
   defp ensure_user_role_loaded(socket) do
     user = socket.assigns[:current_user]
 
diff --git a/lib/mv_web/plugs/check_page_permission.ex b/lib/mv_web/plugs/check_page_permission.ex
index ff6d47d..b2f37ec 100644
--- a/lib/mv_web/plugs/check_page_permission.ex
+++ b/lib/mv_web/plugs/check_page_permission.ex
@@ -54,7 +54,7 @@ defmodule MvWeb.Plugs.CheckPagePermission do
         conn
         |> fetch_session()
         |> fetch_flash()
-        |> put_flash(:error, "You don't have permission to access this page.")
+        |> maybe_put_access_denied_flash(user)
         |> redirect(to: redirect_to)
         |> halt()
       end
@@ -75,6 +75,13 @@ defmodule MvWeb.Plugs.CheckPagePermission do
 
   defp redirect_target(user), do: redirect_target_for_user(user)
 
+  # Only set "no permission" flash when user is logged in; unauthenticated users get redirect only, no flash.
+  defp maybe_put_access_denied_flash(conn, nil), do: conn
+
+  defp maybe_put_access_denied_flash(conn, _user) do
+    put_flash(conn, :error, "You don't have permission to access this page.")
+  end
+
   @doc """
   Returns true if the path is public (no auth/permission check).
   Used by LiveView hook to skip redirect on sign-in etc.
diff --git a/lib/mv_web/plugs/oidc_only_sign_in_redirect.ex b/lib/mv_web/plugs/oidc_only_sign_in_redirect.ex
new file mode 100644
index 0000000..9cf2a16
--- /dev/null
+++ b/lib/mv_web/plugs/oidc_only_sign_in_redirect.ex
@@ -0,0 +1,73 @@
+defmodule MvWeb.Plugs.OidcOnlySignInRedirect do
+  @moduledoc """
+  When OIDC-only mode is active:
+  - GET /sign-in redirects to the OIDC flow when OIDC is configured (sign-in page skipped).
+  - GET /sign-in?oidc_failed=1 is not redirected, so the sign-in page is shown after an OIDC
+    failure (avoids redirect loop when the provider is down or misconfigured).
+  - GET /auth/user/password/sign_in_with_token is rejected (redirect to /sign-in with error)
+  so password sign-in cannot complete.
+  """
+  import Plug.Conn
+  import Phoenix.Controller
+
+  alias Mv.Config
+
+  def init(opts), do: opts
+
+  def call(conn, _opts) do
+    conn
+    |> maybe_redirect_sign_in_to_oidc()
+    |> maybe_reject_password_token_sign_in()
+  end
+
+  defp maybe_redirect_sign_in_to_oidc(conn) do
+    if conn.request_path != "/sign-in" or conn.method != "GET" do
+      conn
+    else
+      conn = fetch_query_params(conn)
+      maybe_redirect_sign_in_to_oidc_checked(conn)
+    end
+  end
+
+  defp maybe_redirect_sign_in_to_oidc_checked(conn) do
+    cond do
+      # Show sign-in page when returning from OIDC failure to avoid redirect loop.
+      conn.query_params["oidc_failed"] -> conn
+      Config.oidc_only?() and Config.oidc_configured?() -> redirect_and_halt(conn)
+      true -> conn
+    end
+  end
+
+  defp redirect_and_halt(conn) do
+    conn
+    |> redirect(to: "/auth/user/oidc")
+    |> halt()
+  end
+
+  defp maybe_reject_password_token_sign_in(conn) do
+    if conn.halted, do: conn, else: reject_password_token_sign_in_if_applicable(conn)
+  end
+
+  defp reject_password_token_sign_in_if_applicable(conn) do
+    path = conn.request_path
+
+    password_token_path? =
+      path =~ ~r|/auth/user/password/sign_in_with_token| and conn.method == "GET"
+
+    if password_token_path? and Config.oidc_only?() do
+      message =
+        Gettext.dgettext(
+          MvWeb.Gettext,
+          "default",
+          "Only sign-in via Single Sign-On (SSO) is allowed."
+        )
+
+      conn
+      |> put_flash(:error, message)
+      |> redirect(to: "/sign-in")
+      |> halt()
+    else
+      conn
+    end
+  end
+end
diff --git a/lib/mv_web/router.ex b/lib/mv_web/router.ex
index f115535..591dead 100644
--- a/lib/mv_web/router.ex
+++ b/lib/mv_web/router.ex
@@ -18,6 +18,7 @@ defmodule MvWeb.Router do
     plug MvWeb.Plugs.CheckPagePermission
     plug MvWeb.Plugs.JoinFormEnabled
     plug MvWeb.Plugs.RegistrationEnabled
+    plug MvWeb.Plugs.OidcOnlySignInRedirect
   end
 
   pipeline :api do
diff --git a/priv/gettext/de/LC_MESSAGES/default.po b/priv/gettext/de/LC_MESSAGES/default.po
index 078ef19..383fb1c 100644
--- a/priv/gettext/de/LC_MESSAGES/default.po
+++ b/priv/gettext/de/LC_MESSAGES/default.po
@@ -3854,7 +3854,7 @@ msgstr "Wenn deaktiviert, können sich Nutzer*innen nicht über /register anmeld
 #: lib/mv_web/controllers/page_controller.ex
 #, elixir-autogen, elixir-format
 msgid "Home"
-msgstr ""
+msgstr "Startseite"
 
 #: lib/mv_web/controllers/join_confirm_controller.ex
 #, elixir-autogen, elixir-format, fuzzy
@@ -3895,3 +3895,13 @@ msgstr "Rolle %{name}"
 #, elixir-autogen, elixir-format
 msgid "User %{email}"
 msgstr "Benutzer*in %{email}"
+
+#: lib/mv_web/live/global_settings_live.ex
+#, elixir-autogen, elixir-format
+msgid "Only OIDC sign-in is active. This option is disabled."
+msgstr "Nur OIDC-Anmeldung ist aktiv. Diese Option ist deaktiviert."
+
+#: lib/mv_web/controllers/auth_controller.ex
+#, elixir-autogen, elixir-format
+msgid "Only sign-in via Single Sign-On (SSO) is allowed."
+msgstr "Nur Anmeldung per Single Sign-On (SSO) ist erlaubt."
diff --git a/priv/gettext/default.pot b/priv/gettext/default.pot
index a845e1e..3e2eb5d 100644
--- a/priv/gettext/default.pot
+++ b/priv/gettext/default.pot
@@ -3895,3 +3895,13 @@ msgstr ""
 #, elixir-autogen, elixir-format
 msgid "User %{email}"
 msgstr ""
+
+#: lib/mv_web/live/global_settings_live.ex
+#, elixir-autogen, elixir-format
+msgid "Only OIDC sign-in is active. This option is disabled."
+msgstr ""
+
+#: lib/mv_web/controllers/auth_controller.ex
+#, elixir-autogen, elixir-format
+msgid "Only sign-in via Single Sign-On (SSO) is allowed."
+msgstr ""
diff --git a/priv/gettext/en/LC_MESSAGES/default.po b/priv/gettext/en/LC_MESSAGES/default.po
index d01da60..21314a5 100644
--- a/priv/gettext/en/LC_MESSAGES/default.po
+++ b/priv/gettext/en/LC_MESSAGES/default.po
@@ -3895,3 +3895,13 @@ msgstr "Role %{name}"
 #, elixir-autogen, elixir-format
 msgid "User %{email}"
 msgstr "User %{email}"
+
+#: lib/mv_web/live/global_settings_live.ex
+#, elixir-autogen, elixir-format
+msgid "Only OIDC sign-in is active. This option is disabled."
+msgstr ""
+
+#: lib/mv_web/controllers/auth_controller.ex
+#, elixir-autogen, elixir-format
+msgid "Only sign-in via Single Sign-On (SSO) is allowed."
+msgstr ""
diff --git a/priv/repo/seeds.exs b/priv/repo/seeds.exs
index 7257f8b..c562a43 100644
--- a/priv/repo/seeds.exs
+++ b/priv/repo/seeds.exs
@@ -3,7 +3,9 @@
 #     mix run priv/repo/seeds.exs
 #
 # Bootstrap runs in all environments. Dev seeds (members, groups, sample data)
-# run only in dev and test.
+# run only in dev and test. Skips entirely if bootstrap was already applied
+# (admin user exists), so safe to run on every start. Set FORCE_SEEDS=true to
+# re-run seeds even when already applied.
 #
 # In production (release): seeds are run via Mv.Release.run_seeds/0 from the
 # container entrypoint. Set RUN_DEV_SEEDS=true to also run dev seeds there.
@@ -12,19 +14,25 @@
 # so that eval_file of bootstrap/dev does not emit "redefining module" warnings;
 # it is always restored in `after` to avoid hiding real conflicts elsewhere.
 
-prev = Code.compiler_options()
-Code.compiler_options(ignore_module_conflict: true)
+_ = Application.ensure_all_started(:mv)
 
-try do
-  # Always run bootstrap (fee types, custom fields, roles, admin, system user, settings)
-  Code.eval_file("priv/repo/seeds_bootstrap.exs")
+if Mv.Release.bootstrap_seeds_applied?() and System.get_env("FORCE_SEEDS") != "true" do
+  IO.puts("Seeds already applied. Skipping. (Set FORCE_SEEDS=true to override)")
+else
+  prev = Code.compiler_options()
+  Code.compiler_options(ignore_module_conflict: true)
 
-  # In dev and test only: run dev seeds (20 members, groups, custom field values)
-  if Mix.env() in [:dev, :test] do
-    Code.eval_file("priv/repo/seeds_dev.exs")
+  try do
+    # Always run bootstrap (fee types, custom fields, roles, admin, system user, settings)
+    Code.eval_file("priv/repo/seeds_bootstrap.exs")
+
+    # In dev and test only: run dev seeds (20 members, groups, custom field values)
+    if Mix.env() in [:dev, :test] do
+      Code.eval_file("priv/repo/seeds_dev.exs")
+    end
+
+    IO.puts("✅ All seeds completed.")
+  after
+    Code.compiler_options(prev)
   end
-
-  IO.puts("✅ All seeds completed.")
-after
-  Code.compiler_options(prev)
 end
diff --git a/test/accounts/user_authentication_test.exs b/test/accounts/user_authentication_test.exs
index 1b47165..b759e8a 100644
--- a/test/accounts/user_authentication_test.exs
+++ b/test/accounts/user_authentication_test.exs
@@ -288,4 +288,31 @@ defmodule Mv.Accounts.UserAuthenticationTest do
       end
     end
   end
+
+  describe "register_with_password when OIDC-only is enabled" do
+    alias Mv.Membership
+
+    test "returns error when OIDC-only is enabled" do
+      {:ok, settings} = Membership.get_settings()
+      original_oidc_only = Map.get(settings, :oidc_only, false)
+      {:ok, _} = Membership.update_settings(settings, %{oidc_only: true})
+
+      try do
+        attrs = %{
+          email: "newuser#{System.unique_integer([:positive])}@example.com",
+          password: "SecurePassword123"
+        }
+
+        result =
+          Mv.Accounts.User
+          |> Ash.Changeset.for_create(:register_with_password, attrs)
+          |> Ash.create()
+
+        assert {:error, _} = result
+      after
+        {:ok, s} = Membership.get_settings()
+        Membership.update_settings(s, %{oidc_only: original_oidc_only})
+      end
+    end
+  end
 end
diff --git a/test/mv/mailer_smtp_config_test.exs b/test/mv/mailer_smtp_config_test.exs
new file mode 100644
index 0000000..22325df
--- /dev/null
+++ b/test/mv/mailer_smtp_config_test.exs
@@ -0,0 +1,89 @@
+defmodule Mv.MailerSmtpConfigTest do
+  @moduledoc """
+  Unit tests for Mv.Mailer.smtp_config/0.
+
+  Ensures both port 587 (STARTTLS) and 465 (implicit SSL) work:
+  - 587: sockopts must NOT contain :verify (gen_tcp:connect would raise ArgumentError).
+  - 465: sockopts MUST contain :verify so initial ssl:connect uses verify_none/verify_peer.
+  Uses ENV to drive config; async: false.
+  """
+  use Mv.DataCase, async: false
+
+  alias Mv.Mailer
+
+  defp set_smtp_env(key, value), do: System.put_env(key, value)
+
+  defp clear_smtp_env do
+    System.delete_env("SMTP_HOST")
+    System.delete_env("SMTP_PORT")
+    System.delete_env("SMTP_USERNAME")
+    System.delete_env("SMTP_PASSWORD")
+    System.delete_env("SMTP_PASSWORD_FILE")
+    System.delete_env("SMTP_SSL")
+  end
+
+  describe "smtp_config/0" do
+    test "port 587 (TLS): does not include :verify in sockopts so gen_tcp:connect does not crash" do
+      set_smtp_env("SMTP_HOST", "smtp.example.com")
+      set_smtp_env("SMTP_PORT", "587")
+      set_smtp_env("SMTP_SSL", "tls")
+
+      config = Mailer.smtp_config()
+
+      assert config != [], "expected non-empty config when SMTP_HOST is set"
+
+      sockopts = Keyword.get(config, :sockopts, [])
+
+      refute Keyword.has_key?(sockopts, :verify),
+             "for 587 gen_tcp is used first; sockopts must not contain :verify"
+    after
+      clear_smtp_env()
+    end
+
+    test "port 465 (SSL): includes :verify in sockopts so initial ssl:connect accepts verify mode" do
+      set_smtp_env("SMTP_HOST", "smtp.example.com")
+      set_smtp_env("SMTP_PORT", "465")
+      set_smtp_env("SMTP_SSL", "ssl")
+
+      config = Mailer.smtp_config()
+
+      assert config != []
+      sockopts = Keyword.get(config, :sockopts, [])
+
+      assert Keyword.has_key?(sockopts, :verify),
+             "for 465 initial connection is ssl:connect; sockopts must contain :verify"
+
+      assert Keyword.get(sockopts, :verify) in [:verify_none, :verify_peer]
+    after
+      clear_smtp_env()
+    end
+
+    test "builds TLS mode for port 587 (STARTTLS)" do
+      set_smtp_env("SMTP_HOST", "smtp.example.com")
+      set_smtp_env("SMTP_PORT", "587")
+      set_smtp_env("SMTP_SSL", "tls")
+
+      config = Mailer.smtp_config()
+
+      assert config != []
+      assert Keyword.get(config, :tls) == :always
+      assert Keyword.get(config, :ssl) == false
+    after
+      clear_smtp_env()
+    end
+
+    test "builds SSL mode for port 465 (implicit SSL)" do
+      set_smtp_env("SMTP_HOST", "smtp.example.com")
+      set_smtp_env("SMTP_PORT", "465")
+      set_smtp_env("SMTP_SSL", "ssl")
+
+      config = Mailer.smtp_config()
+
+      assert config != []
+      assert Keyword.get(config, :ssl) == true
+      assert Keyword.get(config, :tls) == :never
+    after
+      clear_smtp_env()
+    end
+  end
+end
diff --git a/test/mv/smtp/config_builder_test.exs b/test/mv/smtp/config_builder_test.exs
new file mode 100644
index 0000000..0b12a52
--- /dev/null
+++ b/test/mv/smtp/config_builder_test.exs
@@ -0,0 +1,83 @@
+defmodule Mv.Smtp.ConfigBuilderTest do
+  @moduledoc """
+  Unit tests for Mv.Smtp.ConfigBuilder.build_opts/1.
+
+  Ensures the single source of truth for SMTP opts correctly handles:
+  - Port 587 (TLS): sockopts must NOT contain :verify (gen_tcp rejects it).
+  - Port 465 (SSL): sockopts MUST contain :verify for initial ssl:connect.
+  """
+  use ExUnit.Case, async: true
+
+  alias Mv.Smtp.ConfigBuilder
+
+  describe "build_opts/1" do
+    test "port 587 (TLS): does not include :verify in sockopts" do
+      opts =
+        ConfigBuilder.build_opts(
+          host: "smtp.example.com",
+          port: 587,
+          username: "user",
+          password: "secret",
+          ssl_mode: "tls",
+          verify_mode: :verify_none
+        )
+
+      sockopts = Keyword.get(opts, :sockopts, [])
+      refute Keyword.has_key?(sockopts, :verify), "for 587 sockopts must not contain :verify"
+      assert Keyword.get(opts, :tls) == :always
+      assert Keyword.get(opts, :ssl) == false
+    end
+
+    test "port 465 (SSL): includes :verify in sockopts" do
+      opts =
+        ConfigBuilder.build_opts(
+          host: "smtp.example.com",
+          port: 465,
+          username: "user",
+          password: "secret",
+          ssl_mode: "ssl",
+          verify_mode: :verify_peer
+        )
+
+      sockopts = Keyword.get(opts, :sockopts, [])
+      assert Keyword.has_key?(sockopts, :verify), "for 465 sockopts must contain :verify"
+      assert Keyword.get(sockopts, :verify) == :verify_peer
+      assert Keyword.get(opts, :ssl) == true
+      assert Keyword.get(opts, :tls) == :never
+    end
+
+    test "strips nil values" do
+      opts =
+        ConfigBuilder.build_opts(
+          host: "smtp.example.com",
+          port: 587,
+          username: nil,
+          password: nil,
+          ssl_mode: "tls",
+          verify_mode: :verify_none
+        )
+
+      refute Keyword.has_key?(opts, :username)
+      refute Keyword.has_key?(opts, :password)
+      assert Keyword.get(opts, :relay) == "smtp.example.com"
+    end
+
+    test "includes adapter and required keys" do
+      opts =
+        ConfigBuilder.build_opts(
+          host: "mail.example.com",
+          port: 587,
+          username: "u",
+          password: "p",
+          ssl_mode: "tls",
+          verify_mode: :verify_none
+        )
+
+      assert Keyword.get(opts, :adapter) == Swoosh.Adapters.SMTP
+      assert Keyword.get(opts, :relay) == "mail.example.com"
+      assert Keyword.get(opts, :port) == 587
+      assert Keyword.get(opts, :auth) == :always
+      assert Keyword.get(opts, :tls_options) == [verify: :verify_none]
+    end
+  end
+end
diff --git a/test/mv_web/controllers/auth_controller_test.exs b/test/mv_web/controllers/auth_controller_test.exs
index e449284..f1fbd76 100644
--- a/test/mv_web/controllers/auth_controller_test.exs
+++ b/test/mv_web/controllers/auth_controller_test.exs
@@ -283,6 +283,141 @@ defmodule MvWeb.AuthControllerTest do
     assert to =~ "/auth/user/password/sign_in_with_token"
   end
 
+  describe "when OIDC-only is enabled" do
+    setup %{conn: authenticated_conn} do
+      {:ok, settings} = Membership.get_settings()
+      original_oidc_only = Map.get(settings, :oidc_only, false)
+      {:ok, _} = Membership.update_settings(settings, %{oidc_only: true})
+
+      conn = build_unauthenticated_conn(authenticated_conn)
+      {:ok, conn: conn, original_oidc_only: original_oidc_only}
+    end
+
+    test "password sign-in is rejected and redirects to sign-in with error", %{
+      conn: conn,
+      original_oidc_only: original
+    } do
+      try do
+        _user =
+          create_test_user(%{
+            email: "password@example.com",
+            password: "secret123",
+            oidc_id: nil
+          })
+
+        {:ok, view, _html} = live(conn, "/sign-in")
+
+        result =
+          view
+          |> form("#user-password-sign-in-with-password",
+            user: %{email: "password@example.com", password: "secret123"}
+          )
+          |> render_submit()
+
+        # When OIDC-only is enabled, password sign-in must not succeed (no redirect to sign_in_with_token).
+        case result do
+          {:error, {:redirect, %{to: to}}} ->
+            refute to =~ "sign_in_with_token",
+                   "Expected password sign-in to be rejected when OIDC-only, got redirect to: #{to}"
+
+          _ ->
+            # LiveView re-rendered (e.g. with flash error) instead of redirecting to success
+            :ok
+        end
+      after
+        {:ok, s} = Membership.get_settings()
+        Membership.update_settings(s, %{oidc_only: original})
+      end
+    end
+  end
+
+  describe "GET /sign-in when OIDC-only" do
+    test "redirects to OIDC flow when OIDC-only and OIDC are configured", %{
+      conn: authenticated_conn
+    } do
+      {:ok, settings} = Membership.get_settings()
+
+      prev = %{
+        oidc_only: settings.oidc_only,
+        oidc_client_id: settings.oidc_client_id,
+        oidc_base_url: settings.oidc_base_url,
+        oidc_redirect_uri: settings.oidc_redirect_uri
+      }
+
+      {:ok, _} =
+        Membership.update_settings(settings, %{
+          oidc_only: true,
+          oidc_client_id: "test-client",
+          oidc_base_url: "https://idp.example.com",
+          oidc_redirect_uri: "http://localhost:4000/auth/user/oidc/callback",
+          oidc_client_secret: "test-secret"
+        })
+
+      try do
+        conn = build_unauthenticated_conn(authenticated_conn)
+        conn = get(conn, ~p"/sign-in")
+        assert redirected_to(conn) =~ "/auth/user/oidc"
+      after
+        {:ok, s} = Membership.get_settings()
+        Membership.update_settings(s, prev)
+      end
+    end
+
+    test "returns 200 when OIDC-only but oidc_failed=1 (avoids redirect loop)", %{
+      conn: authenticated_conn
+    } do
+      {:ok, settings} = Membership.get_settings()
+
+      prev = %{
+        oidc_only: settings.oidc_only,
+        oidc_client_id: settings.oidc_client_id,
+        oidc_base_url: settings.oidc_base_url,
+        oidc_redirect_uri: settings.oidc_redirect_uri
+      }
+
+      {:ok, _} =
+        Membership.update_settings(settings, %{
+          oidc_only: true,
+          oidc_client_id: "test-client",
+          oidc_base_url: "https://idp.example.com",
+          oidc_redirect_uri: "http://localhost:4000/auth/user/oidc/callback",
+          oidc_client_secret: "test-secret"
+        })
+
+      try do
+        conn = build_unauthenticated_conn(authenticated_conn)
+        conn = get(conn, "/sign-in?oidc_failed=1")
+        assert conn.status == 200
+        # Sign-in page is shown, not redirect to OIDC
+        assert conn.resp_body =~ "Sign in" or conn.resp_body =~ "sign-in"
+      after
+        {:ok, s} = Membership.get_settings()
+        Membership.update_settings(s, prev)
+      end
+    end
+
+    test "returns 200 when OIDC-only but OIDC not configured", %{conn: authenticated_conn} do
+      {:ok, settings} = Membership.get_settings()
+      original_oidc_only = Map.get(settings, :oidc_only, false)
+      {:ok, _} = Membership.update_settings(settings, %{oidc_only: true})
+
+      try do
+        conn = build_unauthenticated_conn(authenticated_conn)
+        conn = get(conn, ~p"/sign-in")
+        assert conn.status == 200
+      after
+        {:ok, s} = Membership.get_settings()
+        Membership.update_settings(s, %{oidc_only: original_oidc_only})
+      end
+    end
+
+    test "returns 200 when OIDC-only is disabled", %{conn: authenticated_conn} do
+      conn = build_unauthenticated_conn(authenticated_conn)
+      conn = get(conn, ~p"/sign-in")
+      assert conn.status == 200
+    end
+  end
+
   # OIDC/Rauthy error handling tests
   describe "handle_oidc_failure/2" do
     test "Assent.ServerUnreachableError redirects to sign-in with error flash", %{
@@ -298,7 +433,7 @@ defmodule MvWeb.AuthControllerTest do
 
       conn = MvWeb.AuthController.failure(conn, {:oidc, :callback}, error)
 
-      assert redirected_to(conn) == ~p"/sign-in"
+      assert redirected_to(conn) == "/sign-in?oidc_failed=1"
 
       assert Phoenix.Flash.get(conn.assigns.flash, :error) ==
                "The authentication server is currently unavailable. Please try again later."
@@ -320,7 +455,7 @@ defmodule MvWeb.AuthControllerTest do
 
       conn = MvWeb.AuthController.failure(conn, {:oidc, :callback}, error)
 
-      assert redirected_to(conn) == ~p"/sign-in"
+      assert redirected_to(conn) == "/sign-in?oidc_failed=1"
 
       assert Phoenix.Flash.get(conn.assigns.flash, :error) ==
                "Authentication configuration error. Please contact the administrator."
@@ -334,7 +469,7 @@ defmodule MvWeb.AuthControllerTest do
 
       conn = MvWeb.AuthController.failure(conn, {:oidc, :callback}, unknown_reason)
 
-      assert redirected_to(conn) == ~p"/sign-in"
+      assert redirected_to(conn) == "/sign-in?oidc_failed=1"
 
       assert Phoenix.Flash.get(conn.assigns.flash, :error) ==
                "Unable to authenticate with OIDC. Please try again."
diff --git a/test/mv_web/live/global_settings_live_test.exs b/test/mv_web/live/global_settings_live_test.exs
index e48c44b..92da11b 100644
--- a/test/mv_web/live/global_settings_live_test.exs
+++ b/test/mv_web/live/global_settings_live_test.exs
@@ -110,4 +110,69 @@ defmodule MvWeb.GlobalSettingsLiveTest do
       assert html =~ "SMTP" or html =~ "E-Mail" or html =~ "Settings"
     end
   end
+
+  describe "Authentication section when OIDC-only is enabled" do
+    setup %{conn: conn} do
+      user = create_test_user(%{email: "admin@example.com"})
+      conn = conn_with_oidc_user(conn, user)
+      {:ok, settings} = Membership.get_settings()
+      original_oidc_only = Map.get(settings, :oidc_only, false)
+      {:ok, _} = Membership.update_settings(settings, %{oidc_only: true})
+      {:ok, conn: conn, original_oidc_only: original_oidc_only}
+    end
+
+    @describetag :ui
+    test "registration checkbox is disabled when OIDC-only is enabled", %{
+      conn: conn,
+      original_oidc_only: original
+    } do
+      try do
+        {:ok, view, _html} = live(conn, ~p"/settings")
+        assert has_element?(view, "#registration-enabled-checkbox[disabled]")
+      after
+        {:ok, s} = Membership.get_settings()
+        Membership.update_settings(s, %{oidc_only: original})
+      end
+    end
+
+    @describetag :ui
+    test "OIDC-only hint is visible when OIDC-only is enabled", %{
+      conn: conn,
+      original_oidc_only: original
+    } do
+      try do
+        {:ok, view, _html} = live(conn, ~p"/settings")
+        assert has_element?(view, "[data-testid='oidc-only-registration-hint']")
+      after
+        {:ok, s} = Membership.get_settings()
+        Membership.update_settings(s, %{oidc_only: original})
+      end
+    end
+
+    test "when OIDC-only is disabled, registration checkbox is enabled and can be toggled", %{
+      conn: conn,
+      original_oidc_only: original
+    } do
+      try do
+        {:ok, settings} = Membership.get_settings()
+        Membership.update_settings(settings, %{oidc_only: false})
+
+        {:ok, view, _html} = live(conn, ~p"/settings")
+        refute has_element?(view, "#registration-enabled-checkbox[disabled]")
+
+        initial_checked =
+          view |> element("#registration-enabled-checkbox") |> render() =~ "checked"
+
+        view
+        |> element("#registration-enabled-checkbox")
+        |> render_click()
+
+        new_checked = view |> element("#registration-enabled-checkbox") |> render() =~ "checked"
+        assert new_checked != initial_checked
+      after
+        {:ok, s} = Membership.get_settings()
+        Membership.update_settings(s, %{oidc_only: original})
+      end
+    end
+  end
 end
diff --git a/test/mv_web/live/join_live_email_failure_test.exs b/test/mv_web/live/join_live_email_failure_test.exs
index ef308c6..50a209c 100644
--- a/test/mv_web/live/join_live_email_failure_test.exs
+++ b/test/mv_web/live/join_live_email_failure_test.exs
@@ -2,6 +2,9 @@ defmodule MvWeb.JoinLiveEmailFailureTest do
   @moduledoc """
   When join confirmation email delivery fails, the user sees an error message
   and no success copy. Uses FailingMailAdapter; async: false to avoid config races.
+
+  Ensures SMTP is not configured (ENV cleared, Settings smtp_host nil) so that
+  Mailer.smtp_config/0 returns [] and the Application-configured FailingMailAdapter is used.
   """
   use MvWeb.ConnCase, async: false
   import Phoenix.LiveViewTest
@@ -12,18 +15,21 @@ defmodule MvWeb.JoinLiveEmailFailureTest do
   test "when confirmation email fails, user sees error flash and no success message", %{
     conn: conn
   } do
+    # Clear SMTP config so Mailer.smtp_config() returns [] and FailingMailAdapter is used.
+    saved_env = clear_smtp_env_and_save()
     enable_join_form_for_test()
 
-    saved = Application.get_env(:mv, Mv.Mailer)
+    saved_mailer = Application.get_env(:mv, Mv.Mailer)
 
     Application.put_env(
       :mv,
       Mv.Mailer,
-      Keyword.put(saved || [], :adapter, Mv.TestSupport.FailingMailAdapter)
+      Keyword.put(saved_mailer || [], :adapter, Mv.TestSupport.FailingMailAdapter)
     )
 
     on_exit(fn ->
-      Application.put_env(:mv, Mv.Mailer, saved)
+      Application.put_env(:mv, Mv.Mailer, saved_mailer)
+      restore_smtp_env(saved_env)
     end)
 
     {:ok, view, _html} = live(conn, "/join")
@@ -46,13 +52,36 @@ defmodule MvWeb.JoinLiveEmailFailureTest do
     refute view |> element("[data-testid='join-success-message']") |> has_element?()
   end
 
+  defp clear_smtp_env_and_save do
+    keys = [
+      "SMTP_HOST",
+      "SMTP_PORT",
+      "SMTP_USERNAME",
+      "SMTP_PASSWORD",
+      "SMTP_PASSWORD_FILE",
+      "SMTP_SSL"
+    ]
+
+    saved = for k <- keys, into: %{}, do: {k, System.get_env(k)}
+    for k <- keys, do: System.delete_env(k)
+    saved
+  end
+
+  defp restore_smtp_env(saved) do
+    for {k, v} <- saved do
+      if v != nil, do: System.put_env(k, v), else: System.delete_env(k)
+    end
+  end
+
   defp enable_join_form_for_test do
     {:ok, settings} = Membership.get_settings()
 
     Membership.update_settings(settings, %{
       join_form_enabled: true,
       join_form_field_ids: ["email", "first_name", "last_name"],
-      join_form_field_required: %{"email" => true, "first_name" => false, "last_name" => false}
+      join_form_field_required: %{"email" => true, "first_name" => false, "last_name" => false},
+      # Clear SMTP host so Mv.Config.smtp_configured?() is false and Mailer.smtp_config() returns [].
+      smtp_host: nil
     })
   end
 end
diff --git a/test/mv_web/plugs/check_page_permission_test.exs b/test/mv_web/plugs/check_page_permission_test.exs
index 2798161..76bed74 100644
--- a/test/mv_web/plugs/check_page_permission_test.exs
+++ b/test/mv_web/plugs/check_page_permission_test.exs
@@ -181,13 +181,14 @@ defmodule MvWeb.Plugs.CheckPagePermissionTest do
   end
 
   describe "unauthenticated user" do
-    test "nil current_user is denied and redirected to \"/sign-in\"" do
+    test "nil current_user is denied and redirected to \"/sign-in\" without access-denied flash" do
       conn = conn_without_user("/members") |> CheckPagePermission.call([])
 
       assert conn.halted
       assert redirected_to(conn) == "/sign-in"
 
-      assert Phoenix.Flash.get(conn.assigns[:flash] || %{}, :error) ==
+      # Unauthenticated users are redirected to sign-in only; no "no permission" message.
+      refute Phoenix.Flash.get(conn.assigns[:flash] || %{}, :error) ==
                "You don't have permission to access this page."
     end
   end