docs: add statusRewrites to Traefik Errors middleware example

Add statusRewrites (401 -> 302) to the ForwardAuth with Errors
middleware configuration and a troubleshooting note explaining that
without it, browsers may show a "Found." link instead of
auto-redirecting to the identity provider.

Fixes #3359

Signed-off-by: Nick Nikolakakis <nonicked@protonmail.com>
Signed-off-by: Jan Larwig <jan@larwig.com>
Co-authored-by: Jan Larwig <jan@larwig.com>

docs/docs/configuration/integrations/traefik.md

@@ -79,8 +79,16 @@ http:
           - "401-403"
         service: oauth-backend
         query: "/oauth2/sign_in?rd={url}"
+        statusRewrites:
+          "401": 302
 ```
 
+:::caution Troubleshooting: Browser shows "Found." instead of redirecting
+When using the Errors middleware without `statusRewrites`, the redirect response from oauth2-proxy can be served within the original 401/403 status context. This causes some browsers to display a "Found." link instead of automatically following the redirect to the identity provider.
+
+Adding `statusRewrites` to rewrite `401 -> 302` ensures the browser treats the response as a proper redirect and follows it automatically.
+:::
+
 ### ForwardAuth with static upstreams configuration
 
 Redirect to sign_in functionality provided without the use of `errors` middleware with [Traefik v2 `ForwardAuth` middleware](https://doc.traefik.io/traefik/middlewares/http/forwardauth/) pointing to oauth2-proxy service's `/` endpoint

docs/versioned_docs/version-7.10.x/configuration/integration.md

@@ -225,8 +225,16 @@ http:
           - "401-403"
         service: oauth-backend
         query: "/oauth2/sign_in?rd={url}"
+        statusRewrites:
+          "401": 302
 ```
 
+:::info Troubleshooting: Browser shows "Found." instead of redirecting
+When using the Errors middleware without `statusRewrites`, the redirect response from oauth2-proxy can be served within the original 401/403 status context. This causes some browsers to display a "Found." link instead of automatically following the redirect to the identity provider.
+
+Adding `statusRewrites` to rewrite `401 -> 302` ensures the browser treats the response as a proper redirect and follows it automatically.
+:::
+
 ### ForwardAuth with static upstreams configuration
 
 Redirect to sign_in functionality provided without the use of `errors` middleware with [Traefik v2 `ForwardAuth` middleware](https://doc.traefik.io/traefik/middlewares/http/forwardauth/) pointing to oauth2-proxy service's `/` endpoint

docs/versioned_docs/version-7.11.x/configuration/integration.md

@@ -225,8 +225,16 @@ http:
           - "401-403"
         service: oauth-backend
         query: "/oauth2/sign_in?rd={url}"
+        statusRewrites:
+          "401": 302
 ```
 
+:::info Troubleshooting: Browser shows "Found." instead of redirecting
+When using the Errors middleware without `statusRewrites`, the redirect response from oauth2-proxy can be served within the original 401/403 status context. This causes some browsers to display a "Found." link instead of automatically following the redirect to the identity provider.
+
+Adding `statusRewrites` to rewrite `401 -> 302` ensures the browser treats the response as a proper redirect and follows it automatically.
+:::
+
 ### ForwardAuth with static upstreams configuration
 
 Redirect to sign_in functionality provided without the use of `errors` middleware with [Traefik v2 `ForwardAuth` middleware](https://doc.traefik.io/traefik/middlewares/http/forwardauth/) pointing to oauth2-proxy service's `/` endpoint

docs/versioned_docs/version-7.12.x/configuration/integration.md

@@ -225,8 +225,16 @@ http:
           - "401-403"
         service: oauth-backend
         query: "/oauth2/sign_in?rd={url}"
+        statusRewrites:
+          "401": 302
 ```
 
+:::info Troubleshooting: Browser shows "Found." instead of redirecting
+When using the Errors middleware without `statusRewrites`, the redirect response from oauth2-proxy can be served within the original 401/403 status context. This causes some browsers to display a "Found." link instead of automatically following the redirect to the identity provider.
+
+Adding `statusRewrites` to rewrite `401 -> 302` ensures the browser treats the response as a proper redirect and follows it automatically.
+:::
+
 ### ForwardAuth with static upstreams configuration
 
 Redirect to sign_in functionality provided without the use of `errors` middleware with [Traefik v2 `ForwardAuth` middleware](https://doc.traefik.io/traefik/middlewares/http/forwardauth/) pointing to oauth2-proxy service's `/` endpoint

docs/versioned_docs/version-7.13.x/configuration/integrations/traefik.md

@@ -79,8 +79,16 @@ http:
           - "401-403"
         service: oauth-backend
         query: "/oauth2/sign_in?rd={url}"
+        statusRewrites:
+          "401": 302
 ```
 
+:::info Troubleshooting: Browser shows "Found." instead of redirecting
+When using the Errors middleware without `statusRewrites`, the redirect response from oauth2-proxy can be served within the original 401/403 status context. This causes some browsers to display a "Found." link instead of automatically following the redirect to the identity provider.
+
+Adding `statusRewrites` to rewrite `401 -> 302` ensures the browser treats the response as a proper redirect and follows it automatically.
+:::
+
 ### ForwardAuth with static upstreams configuration
 
 Redirect to sign_in functionality provided without the use of `errors` middleware with [Traefik v2 `ForwardAuth` middleware](https://doc.traefik.io/traefik/middlewares/http/forwardauth/) pointing to oauth2-proxy service's `/` endpoint

docs/versioned_docs/version-7.14.x/configuration/integrations/traefik.md

@@ -79,8 +79,16 @@ http:
           - "401-403"
         service: oauth-backend
         query: "/oauth2/sign_in?rd={url}"
+        statusRewrites:
+          "401": 302
 ```
 
+:::info Troubleshooting: Browser shows "Found." instead of redirecting
+When using the Errors middleware without `statusRewrites`, the redirect response from oauth2-proxy can be served within the original 401/403 status context. This causes some browsers to display a "Found." link instead of automatically following the redirect to the identity provider.
+
+Adding `statusRewrites` to rewrite `401 -> 302` ensures the browser treats the response as a proper redirect and follows it automatically.
+:::
+
 ### ForwardAuth with static upstreams configuration
 
 Redirect to sign_in functionality provided without the use of `errors` middleware with [Traefik v2 `ForwardAuth` middleware](https://doc.traefik.io/traefik/middlewares/http/forwardauth/) pointing to oauth2-proxy service's `/` endpoint