Hi Albert, Thank you for the suggestion — adding the print() statements before passing the credential to Firebase gave us exactly the information we needed. For anyone else hitting this thread, here is what the logs revealed: The Apple Sign-In flow on iOS works correctly. The user can authenticate, the Apple ID screen appears, and we receive a valid ASAuthorizationAppleIDCredential from SignInWithApple.getAppleIDCredential(), including: identityToken: present (918 chars, well-formed JWT) authorizationCode: present userIdentifier: present rawNonce length: 32 The credential is then passed to FirebaseAuth via OAuthProvider('apple.com').credential(idToken, rawNonce), and only at that point does Firebase reject it with: [firebase_auth/invalid-credential] Invalid OAuth response from apple.com So you were right — the Apple side is healthy. The issue is between the credential we receive and how Firebase Auth validates it. We will continue investigating on the Firebase side (provider configuration, nonce handling) and follow up with the Flutter / Firebase community as you suggested. Thanks again for your time. Best regards, Dogukan

Hi, I'm experiencing the exact same "invalid OAuth response from apple.com" error, but with one key difference: in my case the Apple authentication screen never appears at all — the error returns immediately on button tap. This makes me think it might be an Apple backend issue with my Team ID specifically. I posted my full setup here: https://developer.apple.com/forums/thread/826547 Did you ever find a resolution? I'd love to hear if you made any progress after 6 months.

Hi charlesrocher, Did you solve your problem?