Phone screen turns black when talking?

All Android smartphones are doing this. When you are in a call, the screen turns black if you keep the phone in a vertical position. This is to prevent unintentional touches with your cheek on the screen.


To unblock the screen, you can move the phone in a horizontal position or simply press one of the volume buttons from the side of the device.

Sometimes it lags and you need to insist on moving the phone to different positions.