Hi everyone,
We’ve developed an iOS app that is working perfectly across our internal testing environments including:
TestFlight iOS simulators Physical iPhones and iPads within our organization However, during App Store review, the build gets marked as incomplete, and the review team reports the following issues:
Issues Reported by App Review: Login error message: "device token must be string" Sign In With Apple: Reviewers are redirected back to the login screen after authentication. No error message is shown, but the user isn't logged in. Account creation: The team is unable to create a new account using the provided credentials.
Everything functions correctly in TestFlight, simulators, and local builds. The issue only seems to happen in the App Review environment, making it difficult for us to reproduce.
We suspect that push notification permission might not be granted or the token is not being generated in the App Review sandbox environment — leading to a null/undefined value that breaks login.
The "device token must be string" message likely appears when our backend validation expects a string, but receives a different type or undefined.
Also, the Apple Sign In redirect and account creation failures may be related to Keychain, token handling, or review sandbox behaviors.