We are currently facing an issue with implementing "Sign in with Apple" in our iOS application built using Flutter. We've implemented "Sign in with Apple" using Firebase and On attempting to sign in, we are encountering the following error: “Sign-up not completed.”
We have verified that:
The Apple Sign is enabled on our Firebase Project.
The Sign in with Apple capability is enabled in the Xcode project.
The Apple Sign-In capability is enabled for the App ID on our Apple Developer account.
All the certificates were re-provisioned after enabling the capability.
The Bundle ID matches across Apple Developer portal and our app configuration.
The email and fullName scopes are requested in the credential.
Please let us know if you require any additional information. We’re happy to provide whatever is needed. Here's a screenshot attached to explain the problem better