Try unplugging the Connect from power for a couple of minutes and reboot your router.

And if that fails, 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.

What electronics are driving the HiFi speakers?

Thank you GuitarSuperstar, the old unplug it and reboot it option worked!

Paul

This is a known (at least to me and a few other users) and lingering issue with the Connect.  Mine worked for years, and through one replacement (I’m on Gen 2), and then suddenly the Connect started losing sync with the rest of the Sonos network speakers.  Restarting fixes it temporarily but it’ll just drift back out of sync over time.  My temporary fix has been to hardwire the Connect to my internet router and use the Connect as the head node in the group it’s in.  

I think we’re all hoping for a software update to fix this, or an admission that the Connect hardware is out of date and needs to be upgraded to a Port (with perhaps lenient upgrade terms) provided we don’t inherit the same problem with the Port.