Looks to me like port 443 is blocked; the port that is used to establish https connections (secure).
Are you by chance working behind a proxy? If you are, make sure that both the http and https entries are filled in and checked in the network preference pane.
Go to System Preferences->Network and see if you are getting an IP from network (use the 'Advanced' button). While there turn off IPv6 and at the top of the Network pane make a new "Location" (call it what you want). This way you can start fresh and get a new IP.
Well were you getting an IP?
An IP. You know that magical number that gives your computer an number so it can communicate on the network.
I again to ask a simple question. Did you get an IP from the router?