Lumia 920 - why don't I have sound when and after making a call?

[BackToTheFuture]

Lumia 920 - No sound when and after making a call

Hi guys,

I am having problem with my 920: whenever I make or receive a call (cell voice, Skype ...), all sounds, both input and output, become mute. I have to soft reset to fix it, but the the problem reappears again when I make a new call.

Does anyone know what causes the problem and how to fix it?

Thanks,
Hai