Same issue here. Ring 2 been working fine for past few years. I noticed it went offline a month or two ago. Finally got around to looking into it today and found the battery completely dead. Measured the wires on the back and get 20V AC. _ _
Charged the battery inside for an hour or so, put it back in and the doorbell powered up. I had to reconnect it to WiFi. It started getting a firmware update, so hoping whatever problem that happened with previous firmware is fixed in this version. However, the power status says its losing power.