Most often, this is caused by network issues, between your controller and the speakers. I’d certainly check the wifi interference FAQ, as well as performing a Sonos network refresh, by unplugging your Sonos devices from power (or powering them off, if battery connected), and rebooting your router. Once the router has recovered, power back on your Sonos devices. This will give them both a fresh IP address, as well as a refresh of the Sonos OS. Finally, check your system for updates, in case there are any that need to be applied. 

Appreciate the suggestion Airgetlam.  Will try.  I was hoping to avoid as this is a solid hour of plugging and unplugging and up and down and up and down stairs.  Plus all the other devices in the house which inevitably need a reset with a new iP.  But I suspect your right.  

Well, the other option, which does essentially the same thing, is to set up reserved IP addresses in your router’s software. If you can. The router I had (replaced yesterday, haven’t looked at the new one yet) didn’t allow that, but my older Netgear did. But eventually, I think that onerous ‘reboot of every device’ needs to be done. 

I’m somewhat ‘lucky’ (?!) in that I live on an island, and the power goes out fairly frequently. But then I don’t really know if my router is smarter, and handles the potential for duplicate IPs better, or it’s just a matter of both the router and speakers resetting each time my power goes out.

Task for today: find out if this new T-Mobile router finally allows me to reserve IP addresses. Something to look at during football. 

OK, this is ridiculous.  After months of utter uselessness, I think we’re in a better place because my toaster died yesterday.  The breaker covering about 25% of our home blew, which included a few speakers.  Power is back and we’re pretty close to normal.  Madness.  Got my Sonos back, and a new toaster.

Lol.  That’s good news.  I would still be very inclined to assign reserved IP addresses in your router for all your Sonoa gear.

The launch of the new app was a total mess. Even a Sonos fanboy like me would sound (and be) ridiculous arguing otherwise.  One of the unfortunate hangovers of the problems experienced is that if a Sonos system isn’t working properly, the “new app” is now automatically blamed.  This stops people looking for he real problem, which may be something else not working optimally in Sonos or in the networking infrastructure.  You were obviously open to this possibility, but had the good fortune to have a toaster do the job for you.