I have a huge music library, over 10 years of music with files all stored on my iMac. 98% ripped from my on CDs or converted from LPS. So now that I also have an iPhone and a MacBookAir, decided to subscribe to iTunes Match. So it had to load/match/upload to the cloud. That process ran for about 3 days uninterrupted, and at the end I discovered tat over 70% of my music could not be played on my iPhone or MacBook Air due to this BOGUS not available in your country or region.
What corrects this is deleting the song from your library, then re adding this. As this would involve thousands of songs, I was hoping something could be done, and spent over 154 hours in two different sessions with 'experts' from Apple support. I had hoped something went wrong with the original 'synch'o the could, so could that be erased and start again from scratch?? Or was there something they could correct? NOTHING every corrected the problem and they had no suggestions.
OK - This weekend I finally finished correcting my cloud library and have everything available on all devices. (Finally after paying for this for over 2 years)
My set up and method. I store all my music on my desktop iMac. When files are added to the library, this is where the files will live. I subscribe to iTunes Match, but NOT Apple Music. My devices all use the same Apple ID. All my music played/plays fine on the iMac.
To correct my iCloud library. Takes 2 devices. EMPTY YOUR TRASH on the main device where good files are. I used album view. On the MacBook Air, look at album and see which songs are greyed out. There are the ones that had the 'unavailable' error. Then open the album on iMac, and for each file greyed on the MacBook Air, select that song and hit the 3 dots and delete from library, and if prompted, move file to your trash.
I keep doing this until I have about 300 files in the trash, max I ever did was 800 at a time.
Create a new folder on your desktop. Open this new folder. Open your trash folder. Select everything in trash, and move them into your new desktop folder. At this point they should all be selected in the new folder, so right-click on one of them and open with MUSIC app. (or make sure you select all, and then right click and open)
This will re-add add the files back into your music library, and trigger an update to the cloud library. I would also usually Go to File --->Library-->Update ICloud Music Library. Give it some time and after you verify that you can play songs on all devices, you can move that new folder on your desktop to the trash and empty your trash.
Today I just finished doing this for my library, that has 27,000 songs in it (2,425 Albums). Worked on this about 3 to 4 hours a day for the past month.
Ask me questions if this process is unclear
