How do I get my Lumia 1520 glance screen to respond?

[Windows Central Question]

Hello! For a couple of days now, I have been experiencing some problems with my Nokia Lumia's 1520 glance screen:

1) Whatever option I choose (regarding duration), it will always time-out as if peek were selected;
2) I cannot use the double-tap function to awake my phone (just the side button will work for that);
3) When I make a call, the screen will go black, as if I had put the phone to my ear and it will not return unless I press the side middle button to wake it up; the same goes for in-call, or whether I want to end a call;
4) When the screen is black, it will not awake if I receive any type of notification. The sound will play, but I have to awake it manually; it will awake if someone calls me, on the other hand...

I don't know if the four problems are related. I've read something about a proximity sensor... but I'm not sure if that's the thing.

I would like to add that the back panel came out a bit (about 5-6 mm) in the upper side of the phone, but I popped it back in. Seems to not be such a perfect fit now, as I can see the inside light, around the top, but just under 1 mm. Again, don't know if related.

I am operating on Windows 8.1, Lumia Cyan update. I have reset my phone several times, still no change.

Please help! Do I need to take it to a Nokia dealer service?
Thanks!

 

[xandros9]

Bingo.
It's the proximity sensor, everything you've stated are signs that somethings up with the proximity sensor.

First, assume its working fine and that something's messing with it, try removing any screen protectors and cleaning the glass.

But otherwise, something's wrong and the sensor thinks your phone is always obstructed. I've heard that some compressed air into the earpiece fixed this issue in a Lumia 920, but I don't know if it will have any effect with any other model.

But all else fails, sounds like a repair job is in order.