Music albums not being recognised in Plex Music

I have a FreeNAS (Free BSD) server running the latest version of Plex Server. When adding my music albums to the system it makes a complete mishmash of them failing to recognise albums completely. Even though my music is all stored in correctly named folders with both File names and tags set correctly to identify the the album, artist, track number and title. Albums like ELO - Discovery, Simon and Garfunkel - Bridge Over Troubled Waters, Carly Simon - No Secrets, Janis Joplin - Pearl, Michael Jackson - Thriller, are not recognised when running a scan. Instead they come up as Unknown Album - Unknown artist. How can this possibly be when iTunes and every other self respecting music manager I have tried instantly recognises and assigns them complete with artwork? Can somebody please explain? As it is I end up having to manually enter the details for each and every track of each and every album. Also, I am too scared to ask Plex to recognise new albums as the re-scan will wipe away all my hard work setting everything back to Unrecognised again. I also have a fairly large collection of classical albums which Plex seems to have even more issue recognising, if that’s at all possible. Please help?

@ODFS-Team said:
Even though my music is all stored in correctly named folders with both File names and tags set correctly to identify the the album, artist, track number and title.

Could you please give an actual example how you name your files and organise them in folders?

Be also advised that on FreeBSD the Plex Premium Music acoustic fingerprinting doesn’t work.

Have you set the AlbumArtist tag in your files as well? Plex needs this for albums.

https://forums.plex.tv/discussion/comment/1050849/#Comment_1050849
https://forums.plex.tv/discussion/comment/1093611/#Comment_1093611

Folder named after the artist then a sub folder named after the album. Each track is then named Artist - Album - Track Number - Track Title. (I have tried other arrangements with the track numbering without making any difference). I did discover via Google search that I am not alone in having issues with Plex becoming stubborn about not allowing files to have the Artist name changed once it has been set for an Album too. Anyway, I seem to have sort of partially fixed it by going into the settings on the server and telling the Agents to use Local Media Assets first for Albums. It still far from perfect though and I still have tracks / albums not being identified or incorrectly identified. Considering these issues don’t happen with iTunes etc. it does indicate the music side of Plex has a fair way to go yet by the look. I love the Movie / TV show side of Plex though and have talked lots of my friends into giving it a try. I just wish it did music better.

@ODFS-Team said:
Plex becoming stubborn about not allowing files to have the Artist name changed once it has been set for an Album too.

Yes, you may need to perform the Plex Dance (for music, without step 4)
after editing embedded metadata or changing file or folder names.

Anyway, I seem to have sort of partially fixed it by going into the settings on the server and telling the Agents to use Local Media Assets first for Albums.

This a good idea. If your library is a Plex ‘Premium Music’ library, you also want to change a property of the library: Edit your library, go tp the ‘Advanced’ tab and check ‘use embedded tags’

Each track is then named Artist - Album - Track Number - Track Title

This is probably too much.

I have zero issues with my schema (see my links above):
/Music/AlbumArtist/AlbumTitle/TrackNo. TrackArtist - TrackTitle.ext