No language on soundtrack?

Hi, I have a strange problem. I just watched my Xbox One on Amazon Prime 21 Jumpstreet, but when I wanted to start the 2 part, I only had background noise and music to the movie, the dialogue was gone. I do not know why that is. I have also played other series, which also lacks the dialogue, while everything else is still to hear.

Did you hear about a headset with extra cable? If so, check the cable if it is connected correctly.

Mfg the 2-stroke cacher.

I've already solved the problem by switching from Dolby Digital to stereo. But thanks anyway.