My app has been rejected by App Store review because the sign in with Apple functionality is not working properly. I'm able to reproduce the issue on my end but I don't understand why it's happening.
I have two other apps that implement the same OAuth flow in an identical manner, and those apps have no issues signing in with Apple.
I've copied my OAuth flow to a fresh project to see if that would make a difference, and it gives me the exact same error. In the simulator I get "invalid_request, invalid web redirect URL", and on-device the FaceID authentication fails with a very non-specific "Sign Up Not Completed" error.
I'm completely out of ideas here, so any guidance would be appreciated. Thanks!