Same issue on our team. Native Sign in with Apple sheet completes authentication, then shows “Sign-Up Not Completed”; no credential returned, nothing reaches our backend. Capability (APPLE_ID_AUTH / PRIMARY_APP_CONSENT) and entitlement verified in the signed binary; agreements all accepted; reproduces on multiple devices, Apple IDs and builds since at least 21 Oct 2026. Deleting and recreating the capability did not help. App Review reproduced it and rejected us under 2.1(a). Team ID: 27FK35NV9Z Bundle ID: com.cocowtchan.surfphotoapp Feedback: FB25380513 (with sysdiagnose) Support case: 103014668055 Requesting the same server-side registration fix applied to GW7XA5CX69 and FRL3DTJQ62.