Specific URL Blocked
There may be packet loss occurring on your network. Try pinging the site.

Windows:  ping www.viki.com(Windows will auto 6 pings)
Linux:    ping -c(x) www.viki.com(where x is the number of times to ping)

If the result is that there is substantial packet loss(above 10%) try clearing your DNS Cache.

Windows: type cmd within Windows search to get Command Terminal then type:ipconfig/flushdns at the C:>
Linux: Depends on the Linux distro.  usually located in /etc/init.d  Once in the /etc/init.d directory see if there is a file named "dns-clean"  if there is just type:  ./dns-clean  then try to log on to www.viki.com again.  Hope this helps but keep in mind that there could be other causes for your problem but this is a good start.  Good Luck!