I can not complete the call

[AC Question]

Smartphone Doro 8030, Android 5.1.1.

I make a call. When I approach the device to my ear, that is, darken Proximity sensor, - my screen fades and remains dark when I remove it from the ear, and I can not complete the call even by pressing the Power button, while my interlocutor does not make End a call. When I'm not approach the device to the ear, do not darken Proximity sensor - everything works as it should.

How to fix it?

 

[B. Diddy]

Welcome to Android Central! Something is either blocking the proximity sensor (and making it think you have the phone up against your ear at all times), or there's something wrong with the sensor itself or the phone's firmware. Do you have a case or screen protector on? If so, try taking them off. Or, at the very least, make sure the screen protector is very clean where it overlies the proximity sensor (which is usually right near the front-facing camera).