App rejected because crash on ipad 15.2.1

App must work on iPad, at least in "small screen" mode.

You should fully symbolicate those crash reports to understand what's happening. It's likely you force unwrapped a nil value, and the fully symbolicated crash report will tell you where in your code you did so. Also, you should ensure you're thoroughly testing the app in order to catch this scenario before submitting a build to App Review; we have an entire guide that's meant to help you catch such errors.

 I think that the app is in foreground for a long period of time and after that crash because a garbage colector or something like that. Thanks.

Neither of these is correct. If you analyze the crash report's two timestamps, launch time and the time of the crash, you'll see the app has been alive for only 3 minutes. None of Apple's platforms use garbage collection. The above advice about symbolication and testing will help you see where your code failed, and how to test better to catch this situation.

Hello Edford. Crashes reports was the ones that review team send us. On our devices or simulator there is no crash. When we test locally on an ipad simulator, there is no answer from apple authentication screen (but there is no crash on the app). When we test using test flight on our real devices, everithing works fine. In fact there have been no changes on our app in the authentication functionality on the last months.

Crashes reports was the ones that review team send us.

Right — you need to symbolicate them to make them useful. Please do that by consulting the document I provided above.