Fix Firefox error message error code sec_error_bad_signature
In Firefox the error code "sec_error_bad_signature" may occur. You can only correct the error if you know the exact source. We present the most common causes.
Fix sec_error_bad_signature: Deactivate family settings in Windows
Many users complain about the error message after upgrading to Windows 10. Most of the time it is related to the Microsoft Family settings. To avoid the error, you need to change the restrictions through the family settings.
- Log in to this Microsoft website with your Windows account.
- Then select the person from whom you want to remove the website restriction.
- Now set the "Block inappropriate websites" switch to "Off" under websites. After that, the error should no longer appear in Firefox.
- It becomes more difficult if you want to keep the family settings activated and still want to eliminate the error. In this case, you have to import the SSL certificates for the relevant pages individually on each device.
- Microsoft offers a detailed tutorial for this case. You can find it under the "Known Issues for Firefox Users" section.
Another source of errors: Avast Antivirus with Firefox
Avast and other antivirus programs increasingly offer so-called "HTTPS scanning". This actually searches encrypted connections.
- However, this only works if the data stream is decrypted with the correct SSL certificate. In other words, this is a "man-in-the-middle attack" in the good sense.
- However, this practice also triggers the "sec_error_bad_signature" error in Firefox. Therefore, open the Avast user interface and navigate to the settings.
- Click on "Active Protection"> "Customize next to Web Shield".
- Remove the checkmark at "Enable HTTPS Scanning" and confirm with "OK". The procedure is similar for other antivirus programs.
We'll also explain how to fix the "sec_error_unknown_issuer" error code in Firefox.