I have a OpenVPN reverse proxy that is working fine except that all users that connect have the ip address

I read that its likely an IPTables issue but im unable to find the rules i need.

I have one firewall rule on both VPS's that i suspect is causing the problem but im not sure:

iptables -t nat -A POSTROUTING -j SNAT --to-source 198.251.81.X
P.S. I have an OpenVPN server on an OpenVZ and KVM VPS.

Can anyone help me?