For me playback works in the web interface and in the app, but not through a Sonos integration. https://accounts.spotify.com/ is down, so if you are not already logged in, you would not be able to.

Yes, seems https://gew4-spclient.spotify.com/track-playback/v1/devices returns HTTP 503 "try again later" currently.

yes that's what i found on dev tools as well, it's working now

works for me again