Mine stopped working the other night as well. I went into the app and then logged in again. After logging in again I went to the Ring API Virtual Device and hit Initialize and then Refresh and everything started working again.
Finally back from some camping and getting back into this...
Nothing so far has worked, until this morning
This time I went into the Ring App and re-discovered devices, the app indicated it was adding in the base station... (even though it is listed as a device) Ran the Hub through the modes, Home > Evening > Sleep and back to Home and the alarm set as desired