Apple users people complaining Face ID fail on iPhone XR/Xs/X/10 for a while. But since the iOS 12.1.1/12.1/12 update, this issue seems to occur more frequently.
Here we’ve gathered some solutions from users’ feedback and our test to fix unable to activate Face ID on iPhone issue, take a look and have a try.
1. Set Date and Time to Set Automatically
Face ID stop working on iPhone X may be related to the date changing. Some users have set the date on their new device to avoid the Springboard crash prior to iOS 12 update. Settings -> General -> Date & Time to set the date and time to set itself automatically and restart iPhone and the Face ID should response normally.
2. Reboot iPhone
Method 2 Hold the side button and volume button; drag the “slide to power off” turn off iPhone X. Press the power button to reboot it.
If the Face ID still won’t on after restating, follow the steps to force reboot your iPhone X. Press the Volume Up button and release, and then press the Volume down button and release. Finally press and hold the side button until the Apple logo appears on iPhone screen.
3. Reset All Settings on iPhone
If you are encountering a more complicated situation and the above methods failed to fix Face ID problems, reset all settings on your iPhone X could be a fine choice.
Go to Settings -> General -> Reset -> Reset All Settings