Sign in with Apple fails with "Sign-Up Not Completed" — reproduces for multiple independent Apple ID accounts, blocking App Store submission

App: Subio - Quản lý đăng ký Bundle ID: io.ausynclab.subio Team ID: DMB7A87LM9 App Store Connect App ID: 6785710632

SUMMARY

Sign in with Apple in our app consistently fails during the account-creation flow with the system error "Sign-Up Not Completed" (shown by iOS's own native AuthenticationServices UI, before any of our app code runs). This has caused App Review to reject our app 5+ times over the past week (builds 16, 17, 19, 20, 21, 22), each citing Guideline 2.1(a) with this exact error.

KEY EVIDENCE THIS IS SERVER-SIDE, NOT APP-SIDE

  1. The failure reproduces for TWO COMPLETELY INDEPENDENT Apple ID accounts:

    • Our own developer test account (used repeatedly since build 16)
    • Apple App Review's own test account/device (different devices each time: iPad Air 11" M3, iPad Air 11" M4, iPhone 17 Pro Max — running iPadOS 26.5.2 and iOS 27.0)

    Two unrelated accounts hitting the identical failure strongly suggests the issue is in our app's Sign-In-With-Apple server-side registration (tied to our Team ID/Bundle ID), not any individual user's account state.

  2. Our backend receives ZERO HTTP requests at the moment of failure, confirmed via server-side logging. This proves the failure occurs entirely within iOS's native account-creation sheet, before our JavaScript code (or the identityToken) is ever produced.

TROUBLESHOOTING ALREADY COMPLETED (to save engineering time)

We have verified all of the following are correctly configured, and the issue persists regardless:

  • Bundle ID capability: APPLE_ID_AUTH is enabled with APPLE_ID_AUTH_APP_CONSENT = PRIMARY_APP_CONSENT (confirmed via App Store Connect API)
  • Provisioning profile: App Store distribution type, contains com.apple.developer.applesignin entitlement (Default), correct Team ID
  • Signing certificate: valid iOS Distribution cert, serial number matches the certificate linked to the provisioning profile in App Store Connect
  • Entitlements embedded in the actual signed, submitted binary (extracted directly from the .ipa and inspected with codesign -d --entitlements) match expectations exactly
  • Tried requesting full scopes (FULL_NAME + EMAIL), reduced scopes (FULL_NAME only), and zero scopes at all (requestedScopes: []) — the failure is identical in all three configurations
  • Added a guard to prevent concurrent/duplicate calls to signInAsync() (in case of rapid double-taps) — failure persists
  • Confirmed the failure occurs both when the button is presented inside a React Native Modal and when presented on a plain (non-modal) screen — ruling out a presentation-context conflict

WHAT WE'D LIKE APPLE'S HELP WITH

Please check, on your side, whether there is a stuck, incomplete, or corrupted Sign-In-With-Apple account-linking record associated with Bundle ID io.ausynclab.subio / Team ID DMB7A87LM9 that could be causing account-creation requests to fail at the server level. We are happy to provide additional logs, device details, or a screen recording if useful.

We would greatly appreciate guidance, as this is blocking our very first App Store submission and we've been unable to identify anything further to fix from the client side.

Thank you for your time.

Sign in with Apple fails with "Sign-Up Not Completed" — reproduces for multiple independent Apple ID accounts, blocking App Store submission
 
 
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