Forum Response - Websites will not load after Firefox update

If you're having website connection issues after a Firefox update, your third-party antivirus software, such as Avast, might be interfering with Firefox's secure connections. <!-- https://bugzilla.mozilla.org/show_bug.cgi?id=1523701 SEC_ERROR_UNKNOWN_ISSUER since updating to Firefox 65 --> We recommend to uninstall your third-party antivirus software and use the security software offered for Windows by Microsoft: *Windows Security with Microsoft Defender Antivirus ([https://support.microsoft.com/office/windows-security-app-overview-ae70cc96-a9cd-4443-a210-e41cb973d3a6 built-in]) For more information and other solutions, see [[Troubleshoot security error codes on secure websites]].

If you're having website connection issues after a Firefox update, your third-party antivirus software, such as Avast, might be interfering with Firefox's secure connections.

We recommend to uninstall your third-party antivirus software and use the security software offered for Windows by Microsoft:

• Windows Security with Microsoft Defender Antivirus (built-in)

For more information and other solutions, see Troubleshoot security error codes on secure websites.