A Microsoft app for iOS and Android devices that enables authentication with two-factor verification, phone sign-in, and code generation
This seems to be a common issue. The reason may be that one of the top row buttons is stuck in a pressed down position (F1-F12, PrintScreen, ScrollLockm, Pause...). Those buttons are poorly designed and it may not even be visible that one of them is stuck, it may be just a bit tilted. If you have this issue, try checking and unstucking.