Check the date and time and time zone in the clock on your computer: (double) click the clock icon on the Windows Taskbar. Check out why the site is untrusted and click the "Advanced" button to expand this section to see extra details. If the certificate is not trusted because no issuer chain was provided (SEC_ERROR_UNKNOWN_ISSUER) then see if you can install this intermediate certificate from another source. You can click the "Advanced" button to expand this section and show extra details. If the certificate is not trusted because no issuer chain was provided (SEC_ERROR_UNKNOWN_ISSUER) then click the blue error message to expand this section and show the certificate chain. You can click "Copy text to clipboard" and paste this base64 encoded certificate chain text in a reply. That will allow us to details like the issuer of the certificate. *https://support.mozilla.org/en-US/kb/troubleshoot-SEC_ERROR_UNKNOWN_ISSUER *https://support.mozilla.org/en-US/kb/what-does-your-connection-is-not-secure-mean *https://support.mozilla.org/en-US/kb/troubleshoot-time-errors-secure-websites *https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message ---- 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. *always be cautious when you get an 'Untrusted' error message *never create a permanent exception without investigating the cause and only use this to inspect the certificate