Every time I try to play mewithoutYou on a desktop I receive the notification "we can't play this until you allow this artist in the Spotify phone app." When I try to play it on my phone I get the notification "This Song can't be played" I have had the issue for a while and it only occurs with mewithoutYou.
I had the same thing happen. Go to Spotify App on your phone and go to Your Library then Artists. See if there is a Hidden list, in there you will see artists thave have been hidden and cant be played. Press the Red circle and then click Don't Play this Artist, i know it should prolly say Allow this artist but i think its a bug with the new spotify update. Once you do that just close and reopen spotify on the PC and phone and it should work.