The messages "Your connection is not secure The owner of twitter.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website. This site uses HTTP Strict Transport Security (HSTS) to specify that Firefox may only connect to it securely. As a result, it is not possible to add an exception for this certificate. Learn more… Report errors like this to help Mozilla identify and block malicious sites" and "Your connection is not secure The owner of www.adultempire.com has configured their website improperly. To protect your information from being stolen, Firefox has not connected to this website. Learn more… Report errors like this to help Mozilla identify and block malicious sites" comes up for several websites including Twitter, Tumblr, DeviantArt.com google.com & others And other websites, images don't show up None of this happened until after I used the "Refresh Firefox - reset add-ons and settings" feature