Why does the Redmi 13C 5G not turn off the screen during a call?

The reasons for the Redmi 13C 5G not turning off the screen during a call are listed below:
1. The function of turning off the screen during a call detects the distance between the face and the screen. If the distance of the ear touching the screen is too small or the angle is too large during the call, it will be detected that the face does not get close to the screen, resulting in the screen not being turned off;
2. The upper part of the phone screen should maintain a large area of touching the face or ears, and the angle between the screen and the face should not be too large.