''locking this thread as duplicate, please continue at [https://support.mozilla.org/questions/1121461 /questions/1121461]'' Getting insecure connection error on every website on https including google.com, twitter.com, mozilla.org. Also I am unable to add exception as these sites implement HSTS, please see attached image. I can fix this issue by resetting firefox, but it keeps coming again and again after few days of use.