Your security software can sometimes be overzealous. It's worth checking if it's the cause.
Standard DNS servers provided by your local provider can block your access. Switching to an open public registry circumvents these local blocks. Open your system's network configuration settings. wwwxvideo com fix
If your computer is trying to reach an old IP address for the site, it will fail to load. Flushing the DNS forces a fresh look-up. Your security software can sometimes be overzealous