Ring devices, such as Ring doorbell cameras and security systems, often use a 2.4GHz Wi-Fi connection for communication. This frequency is used because it typically offers better range and coverage, making it suitable for devices that might be placed farther away from the router or used outdoors
Make sure that you are typing the Default Wi-Fi name and password correctly without any errors. The Wi-Fi password is not required to have any space in between and also, type the alpha characters in “upper case “if still unable to connect try with “lower case”..
If you are not able to connect with the Default Wi-Fi name and password you can try customizing it :
Click the below link for the same :
http://arris.force.com/consumers/articles/General_FAQs/SBG8300-Changing-the-Wi-Fi-Name-and-Password
Also, Try reaching the Security mode, log in to the web manager (192.168.0.1 ) select Gateway« Connection « Wi-Fi « Network « and change the Wi-Fi Security Mode from WPA2-PSK(AES) Recommended to WPAWPA2-PSK (TKIP-AES).
For the NordVPN issue recommended to contact the NordVPN manufacturer.