hello apferraresi, can you share the url of the secure page you're having issues with?

HI apferraresi, There have been a few updates in the last year for types of security certificates.

However if you are visiting the same site and still being prompted for adding an exception to the cert may have expired or you have not checked the 'always accept this cert' box.

If this happens consistently, please make sure it is not a security attack. You can manually check the certs to see if the issuer is correct, however avoiding untrusted connections is good as well. Please see: "This Connection is Untrusted" error message appears - What to do

The url is https://www.qa2.hq.noths.com/admin/session/new (so this url hits an application existing on a local,internal network server). But it happened with public websites, too. Sorry I cannot name one, I simply avoided using firefox because of this problem and I do not remember.

And I have not checked the 'always accept this cert' box because simply it doesn't work: clicking the button, nothing happens, I'm not let through to see the allegedly unsecure site.

So no secure attack, just this feature of firefox stopped working a while ago.

hello, please try to reset firefox and see if this can address the issue: Refresh Firefox - reset add-ons and settings

Thanks Philipp, sorry I didn't try this solution before.