Make an exception under about:preferences.

answer was incomplete ... need more info could not find "preferences" with regard to allowing a site that firefox deems not secure

Hello, you will find all information about this issue in this documentation page. We cannot recommend you to bypass this warning but you will find all relevant documentation to do it.

Do not hesitate if it does not fix your issue.

I never get the the option "advanced" therefore I never get a chance to override ..... this is a trusted site I'm stuck