Why doesn't my screen shut off during a call?

[Windows Central Question]

My screen doesn't shut off during a call

I frequently press mute/hold/other things with my face during a phone call. I do not have a case or screen protector covering the sensor. Restart doesn't work. Is there some setting that I'm missing?

 

[ven07]

Re: My screen doesn't shut off during a call

Which phone do you have? has this always been the case?