Rythmbox shows UPNP folder structures, but no files or folders under them

Hey dear forum,

I switched from Linux Mint to Zorin OS after getting fed up with Windows, to put it vulgarly.

I am someone who always tries new things and so far I like this OS even better than Linux Mint.

Even my mobile UPnP server (Android/Kodi/Bubble UPnP) shows up in the included Rythmbox, which was not the case with Linux Mint.

However, I now have a new problem it now shows the server also the folder structures, but not the contents or other folders underneath, what could be the reason? (See picture, system is in German)

I'm a beginner with Linux, I've only ever used Windows and everything works there.

Kind regards

Ricardo Wagner

You are welcome to answer me in German or English