I can ping the site from any other internet connection. It fails to load the page in the browser saying it can't resolve the IP address.
<ping>yes I can from here as well.
I did have one such site that failed like yours a year or so ago, and I never managed to resolve the problem.
<thought> You could try disabling the http proxy in the control panel, you might want to reboot to be sure that the change bites (others might confirm or deny this is needed) .