You may experience issues with the non-standard HTTP ports cPanel works with. Usually, cPanel can be opened via:
Sometimes local firewalls allow only access to sites on port 80. In such cases, use the last URL. Note that the third address is a web based proxy which provides you with the option to access your cPanel via the default HTTP port 80. We have set this extra service for our customers whose Internet Service Providers block ports 2082 and 2083.