First track stripped off each album into its own folder. Help!

I have backed up all my my music to my WD My Cloud, in the Public Folder. The albums are in a sub-folder titled ‘Music’ which itself is in a folder called ‘Shared Music’. Each album is a separate folder and all the tracks are numbered 01-16 or whatever the highest track number is.

However when I stream direct from the server orI transfer albums to my Windows 10 computer, or android phone the first track of every album is stripped off and listed as a separate ‘unknown album’. This happens in SONOS, Music Bee, and VLC.

I haven’t been able to find a solution, can anyone help?