Well, today I went to play one of my favourite songs, Wish You Were Here, but on the album it was dark and didn't have the play button. 2 songs on the album were playable, but the rest were the same as Wish You Were Here, unplayable. These songs were playable just yesterday, but now they aren't. Does anybody know the reason for this? And does anybody know how to fix this?
There, unfortunately, isn't really a fix for this. As mentioned, some artists might make the songs unavailable for certain reasons like copyright or a change in available countries. The artist could always make them available again after a while, for now the best solution is to either listen to the song through Youtube or to download/buy the album to add them to your local library in Spotify.