In cases when the mobile app has not recognized the fingerprint three times in a row. In such cases, you will be automatically offered to enter your PIN code.
If you are an iOS phone user, the TouchID function can be blocked by the phone operating system. This happens, for example, when a fingerprint on the phone is not recognized eight times in a row. In this case, you need to unlock the fingerprint feature on your phone first to be able to use it again in the mobile app.
If you add a new fingerprint to your phone, the fingerprint feature will be disabled in the mobile app for security reasons. In this case, you need to reactivate your fingerprint in the mobile app so you can use it again to log in or confirm payments.