Firefox: Fix error code sec_error_unknown_issuer - how it works
If Firefox reports the error code "sec_error_unknown_issuer", the problem can usually be quickly remedied. We'll show you how it's done.
Fix Firefox error sec_error_unknown_issuer
"The certificate is not trusted because the issuer certificate is unknown": If Firefox recognizes the certificate incorrectly, you only have to delete the certificate file. If the following instructions do not help, look for an "SSL scan" option in your anti-virus software and deactivate the function. Before doing so, try the easy way:
- Start Firefox and enter the "about: support" command in the URL bar at the top.
- Click on the "Show folder" button next to the "Profile folder" item.
- Close Firefox and delete the "cert8.db" file in the folder.
- If you start Firefox again, the file will be created again. The bug should be fixed.
