Managed users can’t play music, only the admin account can

Sorry, new here, I have been using Plex for some time, but have just setup & started using managed users for different people in the house (mainly so where each person is up to in a movie/show is retained for them).
Mainly accessing my Plex server via Apple TV’s, iPad or iPhones, but also a laptop using Firefox (when I’m at work).
The problem I have is the managed users (all 3 managed users have the same problem), is they can see/browse all the music in the server, but can’t play anything, (except “sometimes” it will play FLAC files), the ONLY way I can actually play music, is by logging in as the “admin” user, then music plays fine. Everything else video wise plays fine for the managed users. I have checked restrictions etc, can’t find anything turned on. Plex server, and all devices/apps updated as far as they can be. Any help would be greatly appreciated, this has been driving me nuts!

Have you checked this: Managed Users | Plex Support

There are some strange restrictions. I suspect this is a security issue that needs to be fixed.

A new server version has been released to beta.
You might have to wait until this one comes to the Public release.