Do I have to access the control panel using the port number (e.g 2083) at the end?
Not necessarily. If corporate restrictions prohibit outbound access to port 2083, you can still login by using one of the following methods.
A secure method:
It will trigger a warning, because you have not purchased a SSL certificate for this subdomain, but you can safely ignore the warning: Prefix your domain name with https://cpanel.
So if your domain name is mydomain.com, you would enter https://cpanel.mydomain.com/
A HTTP authentication box will come up that will ask you for your username and password. Please use the details as listed in our client area.
An insecure method
Your login details are transmitted in real text if you use this method:
Prefix your domain name with http://cpanel. Ironically, you will most likely not get a warning from your browser for using the most insecure method. Your username and password are transmitted in real text and everyone along the route can possibly retrieve your username and password.