Across our shared hosting network, we have a number of security measures in place to ensure to security of the servers and your hosting account. As part of these security measures, it is possible to get your IP address blocked, preventing you (or anyone else on your same IP address) from accessing your hosting account. The most common reason for getting blocked by a servers firewall is invalid login attempts to mail.
At this time, it is not possible to unblock yourself from the client area. We are working with our developers to add this functionality. In the meantime, if you find yourself blocked on the firewall, simply open a ticket with the Support Dept. and they will unblock you right away.