Sleep issue with Amazon firestick.

I've just downloaded the Deezer app to use on Amazon firestick. Whilst playing music, after a few minutes the screen saver came on and the music stopped playing. Frustrated by this I looked in the firestick settings to find how to turn the screensaver off, which I did. Thinking that would be the end of it I then found that after about 20 mins the firestick went to sleep. I could not see how to change this. It also seems that this issue has been going on for sometime now. Is there a solution to this that I am missing?. If not then why not? There's no point in having the app otherwise as it ruins the experience.