When trying to log on using Firefox, I keep getting error messages:

I then found out that this message appeared for EVERY web site I tried!   It was obvious that the problem was at MY computer.  I checked every setting for Firefox and Avast.

I deleted Firefox and reinstalled it again, thinking that it was the root of the problem. When I tried to launch Firefox again, I still got the SAME error.  I recently had to reinstall Avast because I could not open scan reports.  As soon as Avast was deleted and I did a restart, Firefox worked perfectly.  The offending program was Avast.  I decided to NOT to use that program again!  My computer has worked perfectly ever since.