Turn off the wireless interfaces. Instructions I followed which solved everything: https://bsteiner.info/articles/disabling-sonos-wifi https://bsteiner.info/ar

Turn off the wireless interfaces. Instructions I followed which solved everything: https://bsteiner.info/articles/disabling-sonos-wifi https://bsteiner.info/articles/disabling-sonos-wifi Sonos's spanning tree implementation is problematic (and anachronistic: last I looked, it was using classic STP not RSTP). In a similar situation I've watched them flap away merrily, spitting constant topology change BPDUs at each other through both interfaces. It's not a pretty sight. They seem to me to be totally in denial about it, judging by their forums. Lots of blame-the-customer and blame-someone-else's-device, and very little (or no) technical documentation. I think they are a speaker manufacturer first, a streaming audio interface second, and a networking company a very distant third.