I'm no guru at this but can you ping google? You may have a issue with sites being resolved, converted from the text thing we type in to the actual number address.
If you get a error with that, try ping 18.104.22.168 and see what that gives. If it works with that then you have a resolve issue. Check that you have at least one DNS server in /etc/resolv.conf.
If neither of those work, hmmmm.
Hope that helps.