Google Assistant and Spotify

[matteymann]

I'd like to be able to say "Hey Google, play The Beach Boys," and have it cast onto my Sonos speakers. 
 
I have everything setup up in my Google home app: my Spotify account, all of the Sonos speakers, etc. But when I speak that request, I get a response that says "Sorry, it looks like you haven't set up this account on this media service provider yet."
 
Pandora works with my set up, but Spotify seems to be uncooperative.
 
Google assistant also doesn't appear in the "Voice Assistants & Apps" area. Only Amazon Alexa. See attached screenshots.
 
Please help!