Why does my phone light turn off when I call any one?

[WPCentral Question]

why my phone lights is off when i call any one

when i call any one from my lumia 620 the phone lights will automatically off

 

[xandros9]

Re: why my phone lights is off when i call any one

make sure the proximity sensor is clear (remove screen protectors, clean screen)

Do the Glance and Double-tap-to-wake features work properly?

Normal functionality is the screen going off only when you cover the upper part of the phone (such as when you hold it up to talk)
and turning back on after