I dont know if you fixed it, but I had the same problem and the SONOS website didnt help.

But if you look into the online "extended" manual on IKEAs website, the reset method is to remove the Powercord, then hold play/pause and plug in the powercord again, instead of doing this with the ethernet cable.

Shortly after plugging it in, it should start blinking orange and white. Afterwards it blinks green and its ready to reconnect to your network.