Sign in with Apple error reported by App Review, but impossible to reproduce (iPadOS 26.1)

Hi everyone, I’m currently facing a blocking issue during App Review, and I’d really appreciate some help from anyone who has experienced something similar.

My app was rejected under Guideline 2.1 – App Completeness with the following message:

“An error message appeared after trying to Sign in with Apple. Device: iPad Air (5th generation), iPadOS 26.1.”

The problem is: I cannot reproduce this bug at all, even when testing under the same conditions.

✔ What I tested:

Physical iPad Air M2 on iPadOS 26.1

Physical iPhone devices

iOS/iPadOS simulators (latest Xcode)

TestFlight build (clean install)

Debug build installed via Xcode (device connected)

In every case, Sign in with Apple works correctly:

Authentication sheet displays properly

Callback returns the credential

User is created/logged in without error

No crash, no rejected promise, no empty credential

✔ Environment

Using ASAuthorizationAppleIDProvider + ASAuthorizationController

Default Apple Sign In button

No custom nonce/redirect modifications

No backend processing at login (client-side only)

Works 100% on iPhone and iPad on my side

✔ Additional context

The app review team also noted a second point:

They couldn’t locate a secondary subscription paywall, which is displayed only after dismissing the first paywall. I already clarified this with them, but I'm mentioning it in case it's related to the Sign in with Apple issue — maybe something in the sandbox environment is causing unexpected UI behavior.

❓ My question

Has anyone already seen Sign in with Apple fail ONLY for the App Review team, while:

It works in TestFlight

It works via Xcode installs

It works on the same OS version

It works on the same hardware

Could it be an issue related to:

Sandbox Apple ID?

iPadOS 26.1 on App Review internal builds?

Reviewers blocking popup presentation context?

Missing entitlement although everything is configured correctly?

Presentation anchor issues specific to iPad?

Any help or ideas would be greatly appreciated. I’ve been trying to reproduce this bug for hours without success, so any insight is welcome. Thanks!

Thank you for your post. If you disagree with the outcome of the review, we recommend submitting an appeal to the App Review Board. When filing your appeal, make sure to:

  • Provide specific reasons why you believe your app complies with the App Review Guidelines.
  • Submit only one appeal per rejection.
  • Respond to any requests for additional information before submitting an appeal.

Once you have submitted the appeal we can escalate it to the App Review Board for review. The App Review Board will contact you directly as soon as they've completed their investigation.

Sign in with Apple error reported by App Review, but impossible to reproduce (iPadOS 26.1)
 
 
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