Please provide public link(s) (no password) that we can check out. '''No Personal Information Please ! ''' ----------------- There is security software like Avast, Kaspersky, BitDefender and ESET that intercept secure connections and send their own certificate. https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can https://support.mozilla.org/en-US/kb/firefox-and-other-browsers-cant-load-websites https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message https://support.mozilla.org/en-US/kb/connection-untrusted-error-message http://kb.mozillazine.org/Error_loading_websites

Hi ppferrara, are you able to share the URL of that page? If not, you can test it on this diagnostic page: it shows how different browsers do when trying to connect (assuming they have their default settings): https://www.ssllabs.com/ssltest/ Does that page say Firefox should be able to connect?