Best answer by Airgetlam
Less likely, but still possible, is that your router has lost track of the IP assignments, and has handed out duplicate IP addresses in one of the recent soft reboots that occur when Sonos updates its software. The short term solution to that is to unplug all your speakers from power, reboot the router, and then once the router is back up, plug in each speaker one at a time, allowing enough time between each one for the previous to fully boot up.
The more permanent fix to that is to go into your router's software, and assign permanent addresses to all of your wifi items (not just the Sonos, but you could just do them if you wanted). Takes a little extra effort, but would keep this issue, if it's indeed what is happening, from recurring again.
Important note here....duplicate IP addresses can occur whether you're in wired or wifi modes. And Boost mode is wireless, even though it technically is separate from your own wifi signal. It still gets IP addresses from your router, so it's still possible.
And, if any/all of that fairs, I'd recommend that you submit a system diagnostic within 10 minutes of one of these cut out/ins, and either post the number here, or contact Sonos to discuss it. There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.