DISASSTERB8 did you not read the above posts... they may be 3 years old but they are still true. This is not a plutonium issue. if you are getting flagged for using a VPN (and you claim that you are not) you should reach out to the devs of the server management software that is flagging you. IW4MAdmin is a popular one and likely the one you are having issues with.
As mentioned above, unless you are banned, plutonium will never keep you out of a server... that is the individual server owner who decides that.