I was having problem accessing my web server from my company, my company network only open port 80 for internet access. So it would be impossible if someone trying to do to access CPanel behind this firewall.
But there’s a way for us to access CPanel via port 80 on our server, there’s no change at all both side our network or server. To access CPanel behind company firewall we can go to http://cpanel.domain.com, replace the domain.com with your own domain. For example http://cpanel.leoganda.net
By using this technique we are bypassing the port on our server, and accessing the port 80 over CPanel. So we gain access.