I can't access my cPanelYou may not be able to open your cPanel if your local connection has been limited / filtered. In such cases you should try accessing your cPanel through:
http://cpanel.yourserver.com
Please replace yourserver.com with your server name which can be found in your Customer Area > My account > Manage next to the account you are interested in. There you will see the DNS servers for your domain which contain the yourserver.com server name.
This cPanel address works on the standard HTTP port 80 and it will not interfere with any firewalls.