Ring 2 Setup keeps telling me to connect to network I've already joined.

Hello! I tried to install a Ring 2 Doorbell for my parents. The app tells me to join the "Ring-...." network, even though I have joined it. Repeatedly! I have tried every step I can find online. I've restarted the Ring, the phone, the modem. I've turned off mobile data and bluetooth on my phone. I've tried with another phone. I turned off the advanced data switching. Etc. etc. The ring has the spinning white lights as expected, its broadcasting the network SSID, and my phone is joined to that network, but the app just keeps saying to connect to that network. A hard restart of the Ring didn't help.