It sounds like this may have a temporary block of your IP in the cPanel firewall. This can happen from failed login attempts (all kinds), or too many concurrent FTP connections, etc...
If you are an Advanced Hosting customer, and you find yourself unable to view your website or log into cPanel, please email us your IP address right away. If it is during business hours, please open a chat session with us so that we can unblock you as quickly as possible.