I'm sure others are having this problem too (considering how constantly faulty Spotify is), but I cannot log in to Spotify on my Amazon Fire TV. I've tried using connect and directly logging in, but no luck. I can still play music just fine, but I can't access the Genius settings or simply have the "Now Playing" in the background.
I have Premium, have tried and confirmed the correct username and password (and tried email instead of username as well).
Also, P.S., Hurry up and support Multi-Room Music.