What happens when you try?

http://www.ehow.com/how_11385212_troubleshoot-reset-connection-firefox.html

https://support.mozilla.org/en-US/kb/server-not-found-connection-problem

https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can

https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message

https://support.mozilla.org/en-US/kb/connection-untrusted-error-message

http://kb.mozillazine.org/Error_loading_websites

This Connection is Untrusted is sometimes caused because the computer system clock is wrong. Check the time / date / time zone settings.

Tried all of them. Still the same issue. Only Facebook. Only Firefox.

FredMcD said

What happens when you try?

The address bar shows Facebook, but the page is completely blank. No error message, just a white page.

Many site issues can be caused by corrupt cookies or cache.

• Clear the Cache and

• Remove Cookies
  Warning ! ! This will log you out of sites you're logged in to.

Type about:preferences<Enter> in the address bar.

• Cookies; Select Privacy. Under History, select Firefox will Use Custom Settings. Press the button on the right side called Show Cookies. Use the search bar to look for the site. Note; There may be more than one entry. Remove All of them.
• Cache; Select Advanced > Network. Across from Cached Web Content, Press Clear Now.

If there is still a problem, Start Firefox in Safe Mode {web link} While you are in safe mode;

Type about:preferences#advanced<Enter> in the address bar.

Under Advanced, Select General. Look for and turn off Use Hardware Acceleration.

Poke around safe web sites. Are there any problems?

Then restart.

Remove History For One Site Open the History Manager <Control><Shift> H. In the search bar, enter the name of the site. Right click on one of the listings and select Forget About This Site. This should remove all information, including any passwords / settings.

I appreciate all your attempts to help Fred, but nothing has worked. I get to the facebook login screen ·since I've cleared cache/cookies) but when I enter my info it STILL takes me to a blank page!

I have no problems with any other browser or on my iPhone and iPad. Just my Mac desktop.

I've called the big guys to help you. Good luck.

Now I cannot get Facebook on ANY browser ·FF, Chrome, Safari).

I can get the login page, then when I login, it goes to a blank white page with the https facebook.com url still in the address bar.

You can check the Net log and the Network log in the Web Console (Firefox/Tools > Web Developer) to see if content fails to load or possibly is blocked (file size is zero).

• https://developer.mozilla.org/Tools/Network_Monitor

Use Ctrl+F5 or Ctrl+Shift+R to reload the page and bypass the cache to generate a fresh log.

Try to disable IPv6 (check for other possible causes as well).

• https://support.mozilla.org/kb/firefox-cant-load-websites-other-browsers-can

While I can create/get the net log, I have no idea what the information there means. Other than seeing a green dot with 200 OK (that appears to mean it reached the site, best I can tell) it still does me no good. Since it is now on all browsers, I did not try disabling lPv6.