Playback just cuts off?

[user-removed]

The app, on a Galaxy S6 Edge, will just stop playing after about 5 songs. It will say it's playing, but there's no sound, and the progress bar stays at the beginning.
It won't continue until I open the app, which is very inconvenient when driving. This has been happening for over 2 months for me. I have the app version 5.6.0.701.
Has anyone else had this problem? If so, have you found a solution? Thank you.