How to fix time-based errors on secure websites for Firefox
Many websites use certificates to be secure and to show that they are secure. These are those whose URL begins with HTTPS. This safety certificate is now issued by the issuing authority for a certain period of time. If you now see such errors in your browser Firefox, you may be interested in this article.
Troubleshooting time-related errors on secure Firefox sites
If the time on your system clock is outside the certificate validity period of a particular site, the site will not open. This would cause the error i>Your connection is not secure. If a website certificate is valid from April 2007 to April 2019 and your system clock time was set somewhere in 2005, the website displays the error.