That’s not usually how it works. Sites ban and block IP addresses. Someone going through your VPN caused such issues that Lemmy.world blocked the IP. The VPN is being used to abuse people. That’s not a VPN’s fault, but the nature of the beast.

I personally don’t think a VPN is even necessary with the Fediverse, as none of us are going to collect IP’s. But try changing the VPN’s location or trying a different VPN.