Can't login to the site

For whatever reason, I am unable to login to the site whether as the admin or as a test user. When I put in the user name and password, I get this error message:

Unable to connect
Firefox can't establish a connection to the server at
    *   The site could be temporarily unavailable or too busy. Try again in a few
    *   If you are unable to load any pages, check your computer's network
    *   If your computer or network is protected by a firewall or proxy, make sure
          that Firefox is permitted to access the Web.

Is this a database issue?

Any help would be greatly appreciated