I just had a very similar experience tonight. My Wi-Fi was acting wonky so I rebooted my network devices. A couple hours later I noticed the ring alarm was on cellular backup and not connecting to my network even though all other devices had. Since you can’t just reboot the thing I had to try more. I tried the “join” button to see if I could fix it that way and had no luck. The pair button on the base station which is part of the process was unresponsive.
As a shot in the dark, I pressed the reset button one time. Near as I can tell this reboots the device. It took a minute or so and it then automatically reconnected to the network and was very happy.
Ring - want to be sure you see this. The device is clearly not always reconnecting To Wi-Fi properly. It would be nice if there was a ring article instead of reddit that told me how to reboot the base station.
Love my alarm. I’m sure they’ll sort it out.