Do you get an error message when you try to visit that site?

In what way is Firefox blocking that website?

See:

• http://kb.mozillazine.org/Error_loading_websites

Reload web page(s) and bypass the cache to refresh possibly outdated or corrupted files.

• Press and hold Shift and left-click the Reload button.
• Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
• Press "Command + Shift + R" (MAC)

• https://support.mozilla.org/kb/how-clear-firefox-cache
• https://support.mozilla.org/kb/Deleting+cookies

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode

Yes I do get an error message. I have logged on to the website from another laptop and I can. The error message I am getting are below. Unable to connect

        Firefox can't establish a connection to the server at www.aolmi.org.
        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.

Did you try to clear the cache?

You can also try to reset (power off/on) the router.

See also;

• http://kb.mozillazine.org/Error_loading_websites