IP Address Whitelisting

I need to view content to the users from specific IP addresses and anyone who is not from one of those IP Addresses should see the gated content fallbacks.

I just read the documentation and I still do not understand. I am attempting to block all users except for the IPs in a whitelist so no one except my permission can enter into the network. How do I accomplish this using vpn?
I tried changing DNS by PureVPN DNS, but it didn’t helped me much. I’ve created a seperate whitelist file local and added and as whitelisting, but no help. It doesn’t make sense that sometimes the VPN works but sometimes it doesn’t.
I tried following these guides but still not sure

Anyone been able to unlock gated content based on IP address?