Extend the "unable to resolve user identity" message

Signed-off-by: Fredrik Adelöw <freben@gmail.com>

.changeset/dry-glasses-push.md

@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-auth-node': patch
+---
+
+Extend the "unable to resolve user identity" message

plugins/auth-node/src/sign-in/readDeclarativeSignInResolver.ts

@@ -66,6 +66,8 @@ export function readDeclarativeSignInResolver<TAuthResult>(
       }
     }
 
-    throw new Error('Failed to sign-in, unable to resolve user identity');
+    throw new Error(
+      'Failed to sign-in, unable to resolve user identity. Please verify that your catalog contains the expected User entities that would match your configured sign-in resolver.',
+    );
   };
 }