fkkl - if you are using the same server for cPGS + game servers and cPanel, 127.0.0.1 should be the "core config" IP you use when setting up servers, that public IP shouldn't even be showing up in the download game server package dialogue, try finding the game you set up and change it's "core config" IP to 127.0.0.1 if it's set otherwise. The for downloading the package, select the 127.0.0.1 server.
kevaskous - In WHM you can log into a user's account directly from the "List Accounts" page and clicking on the cPanel icon to be transfered into the user's account, or log in as the user directly like
https://yourserver.com:2083/