Sign in with Apple fails with AuthorizationError 1000 on a brand-new SIWA setup (TestFlight)

Hi all,

I just enabled Sign in with Apple for my app for the first time.

The app is built with FlutterFlow using its native Authenticate with Apple action.

When I tap Sign in with Apple, nothing happens: the Apple authorization sheet never appears.

To investigate further, I created a custom action that directly calls:

SignInWithApple.getAppleIDCredential(...)

and catches any exception.

It consistently returns:

SignInWithAppleAuthorizationException( AuthorizationErrorCode.unknown, The operation couldn't be completed. (Error Domain=com.apple.AuthenticationServices.AuthorizationError Code=1000) )

The app is distributed through TestFlight and the issue occurs on a real device.

I'm wondering whether anyone has experienced the same behavior after enabling Sign in with Apple on a new App ID.

If so:

Did the issue resolve itself after some time? Was there any Apple-side propagation delay involved? Or was there an additional FlutterFlow or Apple Developer configuration that I might be missing?

What I've already verified

✅ Sign in with Apple capability is enabled on the App ID.

✅ Distribution certificate is valid.

✅ Provisioning profile was regenerated after enabling the capability and lists Sign in with Apple under Enabled Capabilities.

✅ Firebase Authentication has the Apple provider enabled.

✅ Google Sign-In works correctly in the same TestFlight build.

✅ Tested only on a physical device via TestFlight.

✅ Rebuilt and redeployed the app from FlutterFlow after every configuration change.

✅ Disabled Firebase App Check enforcement for Authentication as a test (no change).

Any suggestions or similar experiences would be greatly appreciated.

Sign in with Apple fails with AuthorizationError 1000 on a brand-new SIWA setup (TestFlight)
 
 
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