I had a prob with the security certificates' configuration at firefox a few days ago. Since then, I can not access normally at duckduckgo, every time that I attempt to use it a warning appears" This connection is untrusted". If I choose the "add exception" option a message says that this site attempts to identify itself with invalid information". I can not select the "permanently store this exception" either and it is not possible to export the certificate and import it later because a password is required. How can I fix this problem?