Why can’t I use my Face ID
How to fix My Face ID is not available at this time
iPhone 11 Pro Max, iOS 15
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If you still need help, reset Face ID, then set it up again. Go to Settings > Face ID &Passcode and tap Reset Face ID. Then tap Set up Face ID to set it up again.
If Face ID isn't working on your iPhone or iPad Pro - Apple ...
With iPhone 12 models and later using iOS 15.2 and later, you can go to Settings > General > About to see the parts and service history of your iPhone and you can see if the camera has been replaced. If the repair was done using genuine Apple parts and processes, you will see "Genuine Apple Part" next to Camera.
Why do you think future iOS will disable the above?
Do you have a disabled Face ID alert on your device?
Please read the "What to do Next" section in this link, if nothing works as per the instruction given in this link --> If an alert says Face ID has been disabled on your iPhone or iPad Pro