Feb 7, 2009

Fix Invalid Security Certificate Error in Firefox

If you happen to visit sites with self signed security certificates you will notice a error in firefox saying

This site uses an invalid security certificate.

The certificate is not trusted because it is self signed.

(Error code: sec_error_untrusted_issuer)

Firefox shows this message many times while you browse that site. Fortunately there is a way to add the certificate of that site manually. Here is how to do it.

--- Go to Tools --> Options in the menu bar of firefox.

--- Now click on the Advanced tab

--- Now click on the Certificates tab and then on the View Certificates button.
--- Now click on the Add Exception. You will see the following screen.

Here add the site you want to get the certificate to. Then click on get certificate. Firefox will check for the certificate and show it.

--- Now select Permanently store this exception and then press Confirm Security Exception.

That's it you will no longer get the self signed security certificate error for that site. You can also add other such sites following the above steps.


  1. Basically SSL cert. is expired for my localhost. So, when I type https://localhost/ and click on Get Cert. button, the Alert message popups and it disables the checkbox for Permanantly... and "confirm security exception" button too.
    Need help imdly.
    This is really frustrating.

  2. Hello, I am getting this for all sites, even the Mozilla/Firefox website and have to click add exception on every page. I have reinstalled the newest and it still happens. any suggestions? thanks

  3. Try checking time, date, etc. Mine was not correct. Fixed it and no more invalid certificates.

  4. How do I make it so that firefox doesn't look for this? In internet explorer, it just gives a warning, and then allows you to select to go to the site anyway, without ever having to go through the hassle of manually entering an exception. Is there a way to do this for firefox?

    This is a HUGE PAIN for people with laptops who use public wifi, to have to manually enter every local webpage that they ever encounter!

  5. SOLUTION: I tried everything to get past this issue. I would get the dreaded error "security Certificate not valid" on every Secure site I went to. I tried coirrecting the time on the computer as it was suggested that the computer time being wrong was the problem, tried registry fixes, you name it...nothing worked. So here's the skinny, just back up your bookmarks, uninstall Firefox, reboot, run a registry cleaner, reinstall Firefox, re-import your bookmarks...problem solved!!!

  6. Great thanks!

    I was sure you used to be able to override the warning in previous versions. I deleted the certificates relating to the site as one seemed to have been mixed with another (causing the warning). All good now!

  7. how to write site

  8. I was getting the same certificate error and found help. Hope the following will help u too.

  9. So were supposed to do this for every site firefox doesn't like?

    FF is giving me cert warnings on almost every site I go to, INCLUDING FIREFOX'S HELP SITE.

    This only started happening to me after I cleared out some history and whatever other stuff with Crap Cleaner.

  10. thank you so much, i sucess by this way.

  11. This fix worked fine for me. Thanks for this post.
    - Prem

  12. thank you very much, it helped me .

  13. Try checking time, date, etc. Mine was not correct. Fixed it and no more invalid certificates....

    Thanks it works......

  14. Make sure your date and time is correct i had the same problem and thats how i fixed this

  15. thks bro..now i have akses for aps.facebook.com

  16. still when i want to open facebook i'm receiving an url page not facebook's real page

  17. firefox downloader link not working for 17.0b1 or 16.0.1

    To getFirefox not working windows 7, Please visit the link.

    Thanks & Regards
    Lacy Brown

  18. thanks... that solved the problem :)

  19. firefox has updated and no longer has the "add exception" option in the certificates section. any new way to add exceptions?

  20. how to come over This Connection is Untrusted help me...