Doorbell Pro 2 won't connect - strange light pattern

I have a relatively new Doorbell Pro 2. It is hardwired into an existing mechanical doorbell. It worked great for a couple of months then went offline. I've been trying to bring it back to life to no avail. It won't even factory reset. It's currently showing a strange light pattern - doesn't match any of the documented ones. The light goes off, then for about a minute is has a pulsing white light, rinse, repeat. Interestingly, if I press the button it doesn't the normal Ring jingle (on the doorbell itself) and also causes the mechanical bell to ring, but I am completely unable to connect to it over wifi. Again, I've tried factory reset too and it remains in this state. Ideas?