Face ID works great for most users, but there are exceptions. Some people experience problems with technology
If you are one of these users, there are two ways to solve the problem. Help Face ID configure herself or completely reset her settings. Below is how to do it.
how to perfectFace ID
Face ID is designed to learnagain after each failure. When Face ID doesn't recognize your face the next time, just enter your password right away. This will convince the system that you are the owner of the phone, just this time look a little different or are in a different place. Ideally, when entering a password, Face ID will take your face data and integrate it into the saved model.
Here is a quote from the Face ID protection doc:
If the Face ID does not recognize you, but the similarity will be large, and you immediately enter the password, the system will once again scan your face and create a new, slightly modified, mathematical model of the face.
how resetFace ID
If there are too many problems with Face ID, you can configure the function again. First you need to reset all its settings. This will delete the saved face model and all other Face ID information.
Step 1: Go toSettings->Face ID and passcode->ResetFace ID.
Step2: You will see the same screen that you configured Face ID for the first time. This time try to adjust in good light.
Step 3: ClickTo beginand move your head in a circle. Try to stretch your neck as much as possible and scan your face from all angles. The second time, move your head more slowly.
When Face ID is reconfigured, wait a couple of hours until it remembers you again and gets used to the environment.
Also read:10 Face ID Tips for iPhone X Owners