The reason is that normally, cPanel is accessed using non-standard ports: Port 2082 and Port 2095.
However, your firewall appears to be blocking communications with Port 2082 and Port 2095, causing Google Chrome to return you an error.
However, the link that I just gave you uses a standard port: Port 80. Firewalls don't block standard ports such as Port 80, meaning that you were able to use cPanel without failure.
Glad I could help