The servers you are on run Firewall software . So if you find that you can visit the world wide web "EXCEPT" it would seem for your web site, your webmail, your directadmin/cpanel or just about anything to do with your web site, your IP could in fact be blocked, this normally happens after you have tried to login to your cPanel, or webmail a number of times and failed.
You will need to unblock your IP, you are able to do this from your account area under the support tab 'Unblock IP'
Your connecting IP will automatically be populated or you may manually enter an IP to be checked and unblocked if required.
Alternatively you may contact us via support ticket to advise us and remove your IP.
You will need to provide your external IP address, easy way to find this is to visit http://www.whatsmyip.org/