I'm on a Premium (for family) plan.
My desktop client is unable to see my Sonos speakers. My mobile client, which is on the same wireless network, can see them all just fine.
Once I start playing something to Sonos from my mobile client, that speaker/group appears in my desktop client and I can control it fine from there after that point. In fact, I can repopulate my desktop's idea of what Sonos speakers exist by switching to each one on mobile. Once they appear in the device list on the desktop client, I can use the desktop client to switch between them.
This looks a lot like a desktop client bug, but there doesn't seem to be a way to report it to Spotify other than in these forums. Any ideas?
Desktop: v220.127.116.110.gfcf0430f on MacOS 10.14.5
Mobile: v18.104.22.1681 on iPhoneX iOS 12.3.1