I have run into a similar situation. Moved in to a new lennar home as 2nd owner. The Lennar-****** already existed but despite me using the password present in the sticker, it said failed internet. I did have my internet provider move my fios service to the new house and connected the router with the mesh. Still no internet. Just 3 configure me networks and one Lennar-****** network.
I just factory reseted all the APs and the main ruckus in the garage and now even the Lennar-****** has disappeared. How do I make this work?