Huh, Got all the way through a reply before I recognized that you said that you had connected your router and the CONNECT:AMP with an ethernet cable. Did you unplug the BRIDGE at the same time?
I think I'd recommend that you
submit a system diagnostic if you can get it to show up in the controller, 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. Note: Sonos phones (and forum folks) are closed for the weekend, so you may want to
contact Sonos via one of their 24/7 options, either Facebook or Twitter to discuss it.