Your text says PLAYBASE, your tags say Arc, so it may be somewhat confusing to many folks.

In either case, what happens when you plug the sound bar in to your router with an Ethernet cable? Does it show up then?

It might help the folks who want to help you if you were to provide more specifics. Exactly what device do you have? What device is your controller running on? What version of the controller are you running? How is your sound bar connected to your LAN, do you normally have a device wired to your Ethernet, or do you normally connect this to your WiFi? You unfortunately did a factory reset, something that makes diagnosis more difficult. Where is the setup failing, what is the specific error? What kind of router do you have, and what channels/types of signals is it using?