Are you seeing ‘SEC_ERROR_UNKNOWN_ISSUER‘ error code in the Firefox window? If you are seeing this error, then you can’t access any website using Firefox, unless you fix this issue. The main culprit behind this problem is security.enterprises root certificate, which when disabled causes this trouble.
Workarounds–
1. Close any opened instance of Mozilla Firefox on your computer. Launch Firefox again.
2. Temporarily disable the antivirus and firewall on your computer. Try to open any site from Firefox. Check if it works.
Simply follow these steps to fix the issue by enabling the particular root certificate-
Fix- Enable ‘security.
Follow these steps-
1. Open Mozilla Firefox on your computer.
2. In Firefox window, copy-paste “about:config” in the address bar and hit Enter.
3. Now, you will receive a message of caution. Click on “Accept the Risk and Continue” to proceed further.
Advanced Preferences tab will be opened.
4. In the Advanced Preferences tab, click on the Search box and type “security.enterprise“.
5. In the search results, you will notice “security.
6. Click on the arrow sign of the particular option to switch its value to “true“.
7. Click on the home icon just beside the address bar to go to the homepage on your browser.
That’s it! Try to open any website on Firefox.
You will not face this error again. Your problem should be solved.
Sambit is a Mechanical Engineer By qualification who loves to write about Windows 10 and solutions to weirdest possible problems.
S.J. says
Thank you! Just got a new work laptop and I use Firefox 99% of the time as my browser. I was getting this error and now it appears to be gone.
sebastian says
Thanks a lot!!!, you save me!