Most likely, you are trying to access this area via a machine that is behind a firewall, or at a workplace.
To remedy this problem, open port 2082 on your firewall or router. If you are at a workplace, however, odds are you will not be able to access cPanel unless you get in touch with an admin regarding port 2082 access.
Additional, if you are trying to connect via https which uses port 2083 you need to unblock this port as well.
If this is not the problem according to your workplace or firewall specifications, give us a support ticket and we'll look into it.