Is your connection not secure?

Question

Browsers

There was a problem, I installed FireFox 44.0.1 and then when I try to go to absolutely any site, the error "Your connection is not secure", it feeds open all sites with an HTTPS certificate and I think this causes a problem, but Safari also opens for me sites with an HTTPS certificate and everything is working fine, tell me what to do?
(Error code: sec_error_unknown_issuer) absolutely on all sites
OS X EL Capitan 10.11.3

Answer 1

The same thing happened on Windows with Kaspersky. Took down the antivirus, everything began to open correctly.
Look in the direction of antiviruses and firewalls, if configured.