''locking this thread as duplicate, please continue at [https://support.mozilla.org/en-US/questions/1028681 /questions/1028681]'' FACEBOOK - "This Connection is Untrusted - You have asked Firefox to connect securely to www.facebook.com, but we can't confirm that your connection is secure. Normally, when you try to connect securely, sites will present trusted identification to prove that you are going to the right place. However, this site's identity can't be verified. What Should I Do? If you usually connect to this site without problems, this error could mean that someone is trying to impersonate the site, and you shouldn't continue." FIREFOX - "This Connection is Untrusted - You have asked Firefox to connect securely to download.mozilla.org, but we can't confirm that your connection is secure. Normally, when you try to connect securely, sites will present trusted identification to prove that you are going to the right place. However, this site's identity can't be verified. What Should I Do? If you usually connect to this site without problems, this error could mean that someone is trying to impersonate the site, and you shouldn't continue." YAHOO - "This Connection is Untrusted - You have asked Firefox to connect securely to www.yahoo.com, but we can't confirm that your connection is secure. Normally, when you try to connect securely, sites will present trusted identification to prove that you are going to the right place. However, this site's identity can't be verified. What Should I Do? If you usually connect to this site without problems, this error could mean that someone is trying to impersonate the site, and you shouldn't continue."