Anna, this problem was driving me nuts, because I always listen to iTunes at the gym. I'm also not an iCloud subscriber, and the day they make it mandatory (I think that's where there headed, I'm switching to Spotify. I already have an account, so the switch won't be difficult. This problem seems to affect some users, but not everybody, and I don't know why. Everyday less and less of my music was playable. This morning my phone had the out of region message for over 1000 of my songs. I truly believe that the April phone update was responsible, because the problem emerged soon after. It might have something to do wt icloud, or maybe the Meta Text, or data was changed on Apple Music. Honestly I don't know know much about them a do not care, but I wish Apple were more careful wt updates.
The solution I came up with was an accident. I took a chance and deselected every album in iTunes, synched, reselected the music, and synched again. There were still a few problems, so I deselected only the problems, and resynched again, and now it's all good. I think you can just select the artists or albums wt problems, but since it was 75% of my library, it was quicker just to select and get rid of them all. I don't know how long this solution will last, but it might be worth giving it a try.
