Check your system date

system is updated. just doesn't open facebook. why is this browser so much of a hassle?

Hi there!

The possible reason for why the site is showing untrusted certificate are:

  - First, system date is not appropriate.
  - Second , a  possibility of hijacking your account could be there ,check your ports and check the certificate of the site.
  

Try to login by typing the url as https://www.facebook.com If problem persist , Try getting the latest version of firefox. Hope that helps.

still doesn't work

Kindly tell me which version of firefox are you running?

Is it only Facebook or have you seen the untrusted connection error screen for some other secure sites?

A common reason for getting errors on many sites, other than a wrong date, time, or time zone, is some kind of software intercepting your connection. This could be your security software, or malware.

Does the untrusted connection error page show a code in parentheses (separated_by_underscore_characters)? Sometimes you need to expand a Technical Details section of the page to see the code.

Could you let us know what error code or codes you are getting?

Also, do you use Avast, BitDefender, ESET or Kaspersky security software?

Firefox 40

(Error code: sec_error_unknown_issuer)

only facebook

It's a little tricky, but I'd like to see whether we can figure out why Firefox does not trust the Facebook certificate.

If you copy the following internal address and paste it into the address bar and press Enter:

chrome://pippki/content/exceptionDialog.xul

That should open an exception dialog. If you enter

https://www.facebook.com/

in the bar and press Enter, are you able to use the View button to view the certificate? (This doesn't always work for some reason.) If you are able to view it, what information appears for the "Issued by" and "Certificate Hierarchy" in the Certificate Viewer? I have attached a screen shot from a while back showing where this information is found.

Are you able to view that?

A couple other suggestions:

(1) Clear Firefox's cache

Temporary files sometimes create strange issues. This article has the steps: How to clear the Firefox cache. If you have a large hard drive, that might take a few minutes.

(2) Check for a diverted connection

"3-bar" menu button (or Tools menu) > Options > Advanced

Click the Network mini-tab and then the Settings button.

The default of "Use system proxy settings" should piggyback on your Windows LAN/IE proxy settings, but you also could try "No proxy" to see whether that makes any difference.

chrome://pippki/content/exceptionDialog.xul didn't work

fiest said

Kindly tell me which version of firefox are you running?

Look at the right-column of this forum page adjacent to the initial posting.

System Details Windows 7 Firefox 40.0

Hi sonofeire, yeah, that doesn't always work.

One possibility is that there is something at the system level which treats Facebook differently than other sites. Another possibility is that you have an add-on which does something special with Facebook.

I'm sorry this is taking so long to figure out, but here is what I suggest next.

Try accessing Facebook in Firefox's Safe Mode. That's a standard diagnostic tool to deactivate extensions and some advanced features of Firefox. More info: Diagnose Firefox issues using Troubleshoot Mode.

If Firefox is not running: Hold down the Shift key when starting Firefox.

If Firefox is running: You can restart Firefox in Safe Mode using either:

• "3-bar" menu button > "?" button > Restart with Add-ons Disabled
• Help menu > Restart with Add-ons Disabled

and OK the restart.

Both scenarios: A small dialog should appear. Click "Start in Safe Mode" (not Refresh).

Any improvement?

If you can access Facebook without the error in Firefox's Safe Mode, I would be very suspicious of your extensions.

If not, could you view the certificate in another browser, such as Internet Explorer or Google Chrome, to see whether those look normal? Click the padlock in the address bar and look for a certificate information link. On Chrome, you first need to click the Connection tab to see that link. Does it match up with the certificate I posted before?

Can you clarify in what way the chrome URI didn't work?

• chrome://pippki/content/exceptionDialog.xul

Didn't the "Add Security Exception" window open?

Wasn't Firefox able to retrieve the certificate and showed an error message in the exceptions window?