Playback stopping when screen lock on android. What can I do?

Hi all,

I'm running the last version from the playstore on android 7 (lineageOS 14.1). When playing music, the screen locks after a while (as expected) which lead to the song stopping a few minute later.

I diabled battery optimization and tried a few other stuff without success. The problem occurs playing only sound with VLC as well but not newpipe. I would assume there is a 'run in background' or 'allow wifi in background' flag to activate somewhere but I don't find it.

Thanks in advance