Unable to add Ring device in the app (after upgrading the phone)

I am unable to add Ring device in the app. After upgrading the phone I noticed that the device was showing offline. Tried all the troubleshooting steps; Re-installed the app, Reset the doorbell, Deleted the device and tried adding again, Restarted the router… But each time I get the following message - "Unable to join the network “Ring-xxxxxxx”. Any thoughts / suggestions?