If you are reading this, chances are that you are trying to access webmail or the control panel from work, school or perhaps an internet cafe.
The address to your webmail is yourdomain.com/webmail Make sure you use your actual domain name instead of "yourdomain.com"
If you get "page cannot be displayed" or similar errors, and are not able to see even a cPanel page, then chances are also that the network consultant or IT dept for these public terminals has blocked the ports responsible for webmail and/or control panel and/or webmail, typically you will get a DNS error or page cannot be displayed.
A great alternative for webmail that can be checked from virtually any machine is mail2web.com.
Choose advanced login.
Then specify:
(replace "yourdomain.com" with your actual domain)
That should get you past the issues you might have with blocked webmail ports.