Try temporarily connecting it to your router with an ethernet cable and re-doing the setup process.

Logout of the Sonos app close it then reopen it and log back in. Go to the unregistered speaker hit the fix it button. Should connect right away. Had the same issue the other day.

I’ve tried this multiple times but the “fix it” button doesn’t do anything for me.

Just moved to a new location; Have new everything (internet provider, router, etc). I can login, but Sonos One cannot find my internet, or (of course) connect to it. I am loosing my patience and almost getting to the point of what they want, throw it to the wall, brake it in pieces, and get something else. Help (PS.: I saw somewhere someone mentioning that we should never do a factory reset (ever). However did it, just forgot that this is one of the options that they give to us, and since I have no clue of what I am doing… Tried even connect to my router directly, got a green light on the system, but have no idea of what to do after, it has been a guess after another