Select Amazon Prime on remote

[Samsung_ZANLZYs]

I have a brand new Samsung model UN75TU700DFXZA television.  When I select Amazon Prime from my Samsung remote, the sound continues from my Dish Network system. No matter what I try I cannot get the sound to stop. I am forced to use my Dish remote to avoid this.  There must be a way to get this working. I am using a Vizio sound bar and optical cable connected directly to the sound bar from my Dish receiver.

[Samsung_ZANLZYs]

I tried that initially. When I had it plugged into the TV the sound didn't quite match to the mouths on the screen.  Moving the cable to the receiver solved that. 

Thanks for the thought.