The yahoo web page I am wanting to go to is below" 

Thank you, I await your favorable reply.

I have never had this problem before with Firefox. and I recently updated firefox, and I now can't access Yahoo.com where my email is located ? I can access yahoo just fine on all other computers in my home but one, the one computer that, I recently updated firefox . I can't believe that yahoo.com is not safe! or that they have configured their web site incorrectly.....really?. i am speaking about Yahoo.com here! and I can easily access yahoo.com using another computer here in my home. Firefox is stating the following: The owner of mail.yahoo.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. I read the articles I found at Mozilla links. and still I have the problem. I have cleared the cache history. the yahoo web site has https: The yahoo web page I am wanting to go to is below" https://mail.yahoo.com/ Please give me step by step instructions to correct this and a clear explanation for this happening. I am using windows 7 64 bit. and the computer is a desk top. I can go to any other web site I choose but not yahoo.com. ?? Thank you, I await your favorable reply.