You need to have the Anti-cheat client running to connect
If you see this error when trying to connect to the game server, this usually means that you are not running the Anti-cheat or you are trying to connect from the wrong Steam account.
This could also happen if you are not starting the game through Steam, for example if you created a shortcut to the executable file which is in the game folder. You will need to launch the game through Steam or create a proper shortcut from the Steam client.
If none of these solutions work for you, we would kindly ask you to get in touch with us via this link and our dedicated CS team will assist in getting you up and running: Contact Support