Could be your speakers having trouble maintaining a clean connection to the servers. Try a simple network refresh, by unplugging all Sonos devices from power, then rebooting your router. When the router comes back up, go ahead and plug back in your Sonos devices. 

If this doesn’t work, however, I would recommend that you submit a system diagnostic within 10 minutes of experiencing this error message, and call Sonos Support to discuss it, or post the diagnostic number here for a Community Moderator to pick up.

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, there are more options available beyond just the diagnostic analysis.

My Sonos Port is cabled to my router, but my IKEA Symfonisk isn’t. I have restarted my router several times and just unplugged the power from the Port also.

I will post the diagnostic number if/when it happens again.

This happened again and the number of the diagnostic file is 900094613. I really hope Sonos can help me with this.

If it’s the issue I think it may be, all of your Sonos devices need to be powered down / unplugged while you reboot the router. Just restarting the devices at different times won’t make the adjustment necessary. And cabled or not cabled makes no difference to this issue whatsoever. 

After some weeks without problems, it has returned. I have restarted everything, including my Spotify account. The problem seems to appear more often when listening to Spotify than Tidal, and never when I’m streaming radio stations from Tuneinn.

I’m soon desperate, maybe I should connect my CD player again...