Have you refreshed (rebooted) every device on your network?
Airgetiam, thanks.
I disconnected all speakers and rebooted the router. It found all three, but Spotify Connect is only found one of them, although all three are available through the Sonos app.
That does seem odd. I think at this point, I would recommend that you submit a system diagnostic, and call Sonos Support to discuss it.
There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.
When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your Sonos system and network.
That being said...Sonos doesn’t have the ability to “look” at the Spotify software, either. They might be able to pin down some network issues with the speakers, if that’s the concern, but I’m not sure they can fix Spotify’s software.
I have just experienced the same thing. Sometimes after a prolonged wait, say 10 minutes, Spotify is able to find my Sonos speakers. Very frustrating.
What did Sonos say, after you submitted a diagnostic and called them?