unable to activate face id on this iphone

Q:"Hello, I have encountered a huge bug with Face ID. I have started getting Unable to activate Face ID on this iPhone notification. I try rebooting my iPhone and setting timezone detection to automatic but it seems to be useless. Any ideas how to repair it?" - Volodymyr from Apple Community.

You know, iPhone X series or later fully supports unlocking iPhone with scanning the face in place of entering a passcode, which greatly facilitates users. As the successor to Touch ID, the facial recognition system can also make payments, access sensitive data, and offer other advanced features in addition to unlocking the device. But even so, it would have led to trouble like above. For this reason, this post is written here, from which you can get 6 achievable methods.