What is the new router setup you’re now using? Did you remove the old WiFi credentials from the Sonos App and are you using a non-overlapping WiFi channel on the 2.4Ghz band. A bit more info. is needed before suggesting a few things. Perhaps also consider setting the channel-width on the 2.4Ghz band to 20Mhz only to reduce the potential for interference.

Thanks Ken - I’m a one banana mechanic when comes to the tech stuff. This was a plug and go upgraded router from my internet provider. 

I did struggle to connect to the ‘new’ wifi initially, then it seemed to sort itself out. I’ll continue to explore my options and settings.

So through the process of elimination, it appears that having my One unit too close to the Sub Mini seemed to be causing the issue. Took me a while to recognize although I did change my router, it also started after adding my new Sub to the system. By trying to identify if I had a wifi dead zone, separating the two (one on a side table, one under the same table) solved the issue.