I'm having a similar problem, my sonos 5 gen2 has stopped working. It did work and was paired with another sono 5 gen2 speaker which is still working. I have reset it multiple times to no avail. I have 12 speakers and this is the only one not connecting. When resetting it the light flashes green and the chime sounds but will not connect. I tried it on ethernet and that worked. I removed it from my wifi to get a clean reconnect and retried connecting it but to no avail. Can anyone give me clues as to how to get help?