why does my screen turn black wen I'm in a call

[AC Question]

On my Asus ZenFone the screen keeps going black wen I'm in a call and want turn back wen I move it from my ear and its like that on any app I can make a call on

 

[B. Diddy]

Welcome to Android Central! It's normal for the screen to turn off when you bring it to your ear during a call, because that's the proximity sensor in action. If it isn't turning back on when you take it away from your ear, make sure the area over the proximity sensor (which is right near the front-facing camera) is clean and not blocked by anything. An ill-fitting case or a dirty screen protector can cause problems like this.