S7 Edge sound problems

[SotirisStef]

Recently I've had problems with my s7 edge. When i click on the sound button to go from mute to turn on the sound it happens that it wont work and along with it I cant see any videos on any apps or hear notifications from neither apps or calls. I can still call other people and the microphone does work but I cant hear anything when that happens. When I reboot the phone it goes back to working normally and it can also happen it works normally if I call somebody , for some random reason.... I thought it's some kind of update glitch but its really annoying. I've tried getting the sim out and in , and do the USB thingy from the developer settings.
What else could I try? This doesnt happen constantly , but it has happened I missed a call and my morning alarm...

Phone is 5 months old...