"Sign Up Not Completed" on every attempt — first-party ASAuthorizationController implementation, entitlement/profile/capability all verified

Sign in with Apple has never completed for our app. The native sheet presents correctly (name, Share/Hide My Email), but on confirmation it shows "Sign Up Not Completed" with a red exclamation. No identity token is returned; the delegate receives ASAuthorizationError 1001 only after the sheet is dismissed. The failure happens entirely inside the system sheet, before any callback reaches app code.

Environment: iPhone 15 Pro Max / iOS 26.6, TestFlight builds. The Sign In with Apple capability was newly enabled on the App ID five days ago and the flow has failed on 100% of attempts ever since. (I'm withholding the Team ID / bundle ID here since this is public — happy to share them with an Apple engineer via the open support case or a Feedback report.)

Implementation - identical to Apple's "Implementing User Authentication with Sign in with Apple" sample; we even replaced the third-party wrapper we originally used with this first-party version to rule it out, and the failure is unchanged:

let provider = ASAuthorizationAppleIDProvider() let request = provider.createRequest() request.requestedScopes = [.fullName, .email]

let controller = ASAuthorizationController(authorizationRequests: [request]) controller.delegate = self // controller strongly retained until completion controller.presentationContextProvider = self controller.performRequests() Verified correct (not assumed — extracted/inspected directly):

Signed binary entitlements (extracted from the distributed IPA): com.apple.developer.applesignin = (Default), with the correct application-identifier and team-identifier for our team embedded.mobileprovision in the bundle contains the same entitlement App ID capability read back via the App Store Connect API: APPLE_ID_AUTH with APPLE_ID_AUTH_APP_CONSENT = PRIMARY_APP_CONSENT (portal shows "Enable as a primary App ID") Exactly one App ID in the account; no wildcard, no duplicates Program License Agreement accepted; nothing pending Already tried, no change: re-saving the capability in the portal; deleting and re-creating the capability via the App Store Connect API; generating a new provisioning profile after that re-registration and shipping a new build signed with it; Share My Email and Hide My Email; device restarts (iCloud + 2FA active); waiting 5+ days for propagation.

This matches threads 789588, 789418 and 789323, and the service-side configuration issue described in thread 790827 (invalid_client / "Sign Up Not Completed" for developer accounts that created or edited app configurations, resolved server-side with no developer action). A Developer Support case and a TSI are already open.

Question for Apple engineers: with the client implementation identical to the official sample and every developer-side artifact verified, is there anything left on the developer side that can produce this - or can the Sign in with Apple service-side registration for our client_id be checked? This is blocking an App Store release (the app was rejected under Guideline 4.8 and Sign in with Apple is the required remedy). A sysdiagnose captured during reproduction is available, and I can provide the Team ID, bundle ID and case numbers privately on request.

"Sign Up Not Completed" on every attempt — first-party ASAuthorizationController implementation, entitlement/profile/capability all verified
 
 
Q