losing sound

Hi
I am running a WD media player through a Panasonic Viera smart TV for playing movies from a hard drive and also streaming Netflix etc. I use the WD player because it is wireless and I don't have the wireless adapter for the TV, and also the WD media player keeps all of my hard drive movies in the folders that I have arranged them into.
My problem is that when I want to watch Netflix I don't get sound unless I power everything down and restart it ( TV, Hard drive and WD player )
Any ideas guys?