Face unlock doesn't work (Nothing else worked)

What are the most common reasons why Face unlock won't work? How to fix it?

In order for face unlock to work, you need to teach your device to recognize your face, and the sensors responsible for face recognition need to be able to scan and recognize your face.

 The reasons behind this error include:

• The face print wasn't saved in the device;
• Dirt or cloud on the screen in the region where the sensors are;
• Bad angle from which you try to unlock your device;
• Covered face;
• Changes on the face (grown beard, glasses, mask);
• Malfunctioned face recognition sensors;
• Outdated operating system.
  
  

The methods below will show you how to resolve issues with unlocking your device using your face. Check them out, and read them carefully.