Sign in with Apple consistently fails with the sheet error "Sign up not completed" for every user and device we have tested. The authorization sheet presents correctly (name/email choices are shown); the failure happens on completion, so no credential is returned to the app. We have eliminated all client-side and account-side causes and believe this is a server-side registration issue with our App ID, matching previously reported cases that were ultimately fixed on Apple's side (forums threads 716252, 122458, 750633). App details: Team ID: Q7BH7CYU67 Client ID (Bundle ID): com.hohomom.baby (App ID resource id RN35DS29UD) Native flow: ASAuthorizationController identity token verified via Firebase signInWithCredential; audience = the bundle ID (no web Services ID involved) Distribution: TestFlight (external), build 1.0 (1784386654) Feedback Assistant report (with sysdiagnose + akd log): FB23839922 Developer Support case: 102946147992 What we verified (all pass): Delivered IPA binary entitlements: com.apple.developer.applesignin = [Default] (via codesign -d --entitlements). Embedded provisioning profile carries the same entitlement (via security cms -D). Signed with a fresh App Store profile created after a capability reset. Developer portal: App ID has APPLE_ID_AUTH enabled as primary (APPLE_ID_AUTH_APP_CONSENT: PRIMARY_APP_CONSENT). We also disabled/re-enabled the capability and rebuilt — no change. Every embedded target now has the entitlement too — we found and fixed a bundled Controls app-extension (com.hohomom.baby.Controls) that was missing the Sign in with Apple entitlement, added it, rebuilt and re-uploaded. Still fails. App Store Connect: no pending agreements. Apple System Status: Sign in with Apple operational at test time. The tester's Apple ID and device are fine: Sign in with Apple works in third-party apps from other teams on the same device. Device-side: rebooted the iPhone and retried on both Wi-Fi and LTE — same failure. Device log evidence (log collect during a failed attempt): at the moment of the attempt, a freshly spawned akd repeatedly fails to fetch the GrandSlam configuration: akd [com.apple.authkit:core] Bag fetch failed! Error Domain=NSURLErrorDomain Code=-1008 URL: https://gsa.apple.com/grandslam/GsService2/lookup/v2 (x4 consecutive) Could an Apple engineer please check the server-side Sign in with Apple registration state for Team Q7BH7CYU67 / com.hohomom.baby and repair or re-provision it? Full details, the affected Apple ID email, and a sysdiagnose are in FB23839922. This is currently blocking our App Store submission (guideline 4.8). Thank you.