After successfully logging in using apple sign-in. I get back the default response: the authorization code. I send the entire payload to my backend to which I then, use the docs - https://developer.apple.com/documentation/sign_in_with_apple/generate_and_validate_tokens to verify the auth_code. I get back this response. { "error": "invalid_grant", "error_description": "client_id mismatch. The code was not issued to com.example.bundle." } I've checked the bundleId several times. I've created new Identifiers and keys, used those new values instead and I get the same issue. According to the errorResponse - https://developer.apple.com/documentation/sign_in_with_apple/errorresponse documentation: invalid_grant The authorization grant or refresh token is invalid, typically due to a mismatched or invalid client identifier, invalid code (expired or previously used authorization code), or invalid refresh token. Any recommended test solutions to diagnose this issue?