Samsung Galaxy A5 screen does not go blank during calls

[hormazdm]

My Samsung A5 2017 screen does not go blank during calls.
because of which I land up pressing random buttons during calls with face.
I restart my phone and the issue resolves for sometime but it keeps coming back.
pls help

 

[luccajan]

have you rooted your device? Do you know if the proximity sensor is still working (test with an apilication like cpu-z)? since when does it not work anymore?