I can not open facebook page

Hello,

when I try to open facebook page. its not open. given the following message. why ?

The connection has timed out

The server at www.facebook.com is taking too long to respond.

The site could be temporarily unavailable or too busy. Try again in a few moments.
If you are unable to load any pages, check your computer's network connection.
If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.

Regards