Tracks greyed out that ARE available on Spotify. Almost certain this is happening to all tracks imported from iTunes, they're losing their link to the Spotify track. Details below.
I have a lot of playlists. At least one of them, with about 60 songs, has had every song turned grey, except 3 tracks.
In the web player, those 3 show as available, but all of the remainder are greyed out.
On the iOS mobile client, only those 3 tracks are shown as being in the playlist at all, the others are missing altogether.
The help here suggests that it's a licensing issue, that the songs have become unavailable in my region. I can confirm that it is not correct, the songs I've checked are nearly all available / licensed in my region when I search for them.
But - Spotify if you're listening - I think I know what's happening:
This is a playlist that was first created years ago when I installed Spotify, and the Spotify Windows app discovered my music by checking my iTunes playlist, and importing them.
I think only tracks imported that way will all have this problem.
Almost certainly the 3 that are still working in the playlist are ones I added to the playlist after it was imported to Spotify.
I'm guessing that, under the hood, for tracks imported that way, Spotify saves the text of the imported track name, gives those their own ID, and tries a fuzzy match somehow to link to the known Spotify track (a one-off match? a regular process?) Anyhow, whatever maintains those links / matches from the imported track name to the Spotify track - those are what's been lost.
Note: there was a small handful of the tracks in that list were never matched to something on Spotify, and they couldn't match, they're from bands that wouldn't be on Spotify. That's OK. It's the 50-odd that are on Spotify but unplayable that are bugging me.
I had the same problem with a lot of old iTunes playlist I imported when I was still using MP3. Spotify seems not to be able to automatically match the song up with their own catalog when they were originally local files.
I did found however a good workaround to solve this.
Just register on soundiiz. There you convert your Spotify Playlist from Spotify with target platform Soundiiz. After doing this you just convert the new created Soundiiz playlist back to Spotify. And voila, all songs are matched up and playable.