Have you tried a system refresh? Power off all Sonos devices, restart your router and wait until the router has fully restarted, then power on Sonos.

I have but still the same issue. I wish it gave an explanation as to why it’s unable to add. I tried removing existing songs, stations, and playlists from Sonos Favorites to see if it was some quota problem but I still can’t add songs or stations. 

I just noticed all existing songs on My Sonos start with a, b, c, or d. Didn’t seem like a coincidence. So I tried adding a song beginning with “A” and sure enough I could add. But I can’t add “Hotel California”. I could add “Flags”. But not “Goodbye”. So for whatever reason I can add songs beginning with A-F, but not anything else. 

If none of the other Community members comes up with a solution soon, you can submit a diagnostic and post the number here for Sonos staff to pick it up, or you can call Sonos Support with the number.

Thanks, I’ve already created a ticket and shared the diagnostics code via email.

I see there is a partial outage on “Sonos Services”: https://status.sonos.com/?utm_source=embed

It doesn’t explain what “Sonos Services” entail, so I don’t know if this is related or not.

By the way, it got worse -- I can now only add songs beginning with A, B, or C. Can’t add “Flags” or “Drift” anymore. I wonder if I upgrade to S2 it would be more stable.