This site will have limited functionality while we undergo maintenance to improve your experience. If an article doesn't solve your issue and you want to ask a question, we have our support community waiting to help you at @FirefoxSupport on Twitter and/r/firefox on Reddit.

ابحث في الدعم

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

How to fix the sec_error_unkown_issuer error message?

  • 5 ردود
  • 5 have this problem
  • 3 views
  • آخر ردّ كتبه kelvint

more options

On my Mac, when I install Firefox, no matter how much I try deleting the Firefox folder from Application Support, deleting the Mozilla folder in Application Support, deleting 'cert8.db' and letting Firefox replenish the file, and just reinstalling, it will always display the error message, "sec_error_unknown_issuer" error message. If someone could please help, I would largely appreciate it. Thanks, have a nice day!

On my Mac, when I install Firefox, no matter how much I try deleting the Firefox folder from Application Support, deleting the Mozilla folder in Application Support, deleting 'cert8.db' and letting Firefox replenish the file, and just reinstalling, it will always display the error message, "sec_error_unknown_issuer" error message. If someone could please help, I would largely appreciate it. Thanks, have a nice day!

All Replies (5)

more options

Screenshot of the error.

more options

There is security software like Avast and Kaspersky and BitDefender and ESET that intercepts secure connections and sends their own certificate or that incorporates special web shielding features that can block content.

You can retrieve the certificate and check details like who issued certificates and expiration dates of certificates.

  • click "Advanced" to expand the error message
  • click "Add Exception" to open "Add Security Exception"
  • alternatively you can open "Add Security Exception" by pasting this URL in the location/address bar:
    chrome://pippki/content/exceptionDialog.xul
    paste the URL of the website (https://xxx.xxx) in it's location field
  • let Firefox retrieve the certificate -> "Get Certificate"
  • click the "View" button and inspect the certificate
    check who is the issuer of the certificate

You can see details like intermediate certificates that are used in the Detail tab.

Who is the issuer of the certificate?

more options

cor-el said

There is security software like Avast and Kaspersky and BitDefender and ESET that intercepts secure connections and sends their own certificate or that incorporates special web shielding features that can block content. You can retrieve the certificate and check details like who issued certificates and expiration dates of certificates.
  • click "Advanced" to expand the error message
  • click "Add Exception" to open "Add Security Exception"
  • alternatively you can open "Add Security Exception" by pasting this URL in the location/address bar:
    chrome://pippki/content/exceptionDialog.xul
    paste the URL of the website (https://xxx.xxx) in it's location field
  • let Firefox retrieve the certificate -> "Get Certificate"
  • click the "View" button and inspect the certificate
    check who is the issuer of the certificate
You can see details like intermediate certificates that are used in the Detail tab. Who is the issuer of the certificate?

Since I am using a Mac, it was unnecessary for me to have an antivirus (I was using Avast at the time), and it's Web Shield technology could have hindered the security certificates Firefox uses in order to validate the authenticity of an https page. However, I will do some more experimenting and come to you guys with a reply for those of you that do need help. Thank you for the reminder that my antivirus could be the problem though!

more options

kelvint said

Since I am using a Mac, it was unnecessary for me to have an antivirus...

That's a common misconception.

more options

Of course I know it's not COMPLETELY unnecessary, but being a cautious computer user, since OS X is a Unix based operating system, I don't need to worry much about having an antivirus. I have Malwarebytes Anti-Malware in those rare occasions that I need to clean a virus.