Proximity sensor and how to disable it

the proximity sensor that works when you call some one and you put the phone with your ear and the screen goes black. I’m having an issue with it and it has recently started. It used to work only while calling but now its working all the time and when ever my finger or hand goes near it, screen goes blank. Like while playing pubg maybe watching a youtube videoo it any thing comes near the sensor the screen goes blank and lights back up when you remove it