Playing album gets an error

[wendor325]

Some albums give me an error - "Playback Error - Unable to find valid media source to play." but their songs play OK.
Some albums works. I put some pictures in attachment.

What did I set up wrong ?

Thank you for help, I dont know what to look for any more.

[wendor325]

Is it possible that albums play via .pls and .m3u files?
Do I have to have .pls for every album (in album folder) ?
And what is the proper naming for playlists?

[theguymadmax]

Scan your music library with the search for missing metadata option.