I am having the same problem, and have no way of getting in touch with Sonos,, (phone, live chat, messaging), .. radio silence, have tried all kinds of factory reset, re-boots (all kit) - at the end of my tether - please update if you get any joy ?
(I am on iPhone by the way)
I managed to get through on chat. I got disconnected from the chat multiple times. Finally it was suggested to remove the "boost", I had. I have thick walls and Sonos struggles without the boost. Now, I am at least able to connect. I now have the same reliability issues I had prior to getting to the boost, but at least I am connected. Will try and get the boost to reconnect at the weekend, when I have more time.