Lumia 730 screen go black when making a call?solution please

[gopal gupta1]

I want the sloution for this please

 

[jmshub]

When you press the dial button to begin a phone call, your phone screen blanks itself so you aren't actuating functions on the screen while holding the phone against your cheek. If you hold it up to your phone and then pull it away, the screen should light up again. It uses the proximity sensor on the front of the screen.