Not experiencing this issue, it could be a local problem. Either wifi interference or a duplicate IP address is likely. I’d start by unplugging all Sonos from power, then rebooting my router. Wait a couple of minutes, then plug back in the Sonos. Wait a couple of minutes for the Sonos to boot up before testing. And then read the linked FAQ. 

I’d also double check my system for updates, just to be sure I’m running the ‘latest’ build. 

Thank you Bruce. Appreciate your response.

it was rather weird in that I removed and reinstalled app frequently. Also rebooted router several times. Checked to make sure software was current. But did not unplug and reboot Sonos devices.

in any case, it persisted for about 12 hours and suddenly returned. 
An odd phantom event.

Thanks again!

Rick