For the past few weeks I have had endless problems with Firefox, none of which happen in IE. I much prefer to use Firefox but am at the end of my tether. I have uninstalled and reinstalled a few times and followed all sorts of fixes suggested in the forums to users with the same issue, but nothing has worked. I reinstalled again today and now every time I open a new tab and try to access sites such as Facebook, Google, or other well known safe sites I get the same message - which is Your connection is not secure The owner of www.facebook.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 only connect to it securely. As a result, it is not possible to add an exception for this certificate.