Video Doorbell 3 Plus goes offline & won't connect

Just putting a thread here as I have two Video Doorbell 3 Plus units that worked great for about 1 week, then both went offline (first 2 days ago, second yesterday) and refuse to connect to WiFi - neither Change WiFi network in the Device Health app page nor a full factory reset helps. Always end up with 2 white flashing LEDs on the right side (indicating the doorbell was unable to connect to wifi). My 3 other Stick-Up cams work perfectly so I know my wifi is OK. Every other non-ring computer works fine too...