Face recognition is not working for the first time
The face recognition id cannot be set for the first time, it shows the messege that your face is out of the view, when it is no.
iPhone X, iOS 11.2.6
Reboot your phone:
Press and quickly release volume up button
Press and quickly release volume down button
Press and keep holding the power button (keep holding past slide to shutdown) until the Apple Logo appears
When your phone comes back up see if normal operation has been restored.