I am not sure if this problem is on Google's end or Spotify... If I as my Google Home to play something (anything) on Spotify, it says, "ok, here is (whatever I asked for)." Then it is silent for a moment and tells me, "I'm sorry, there was a problem. try again when you are ready."
I can play music without a problem with Google music, but I want Spotify to work. I paid for premium for this reason.