I cannot quote but if I could I would quote Kathy's post # 11. That is what I am getting on both IE9 and Firefox. This happens from time to time and then all of a sudden it will work. I do everything that is suggested but to no avail. This is the first time it has happened with Firefox.
I am not going to download Chrome as I do not believe I should have three different browsers just to try to access one website.
I've used Firefox almost exclusively for years and never had this happen to me. FF was recently updated, and in the process, one of the add ons was removed as it wasn't compatible. It had to do with screening or checking (or something) the safety of visited websites.
I'm definitely no geek, just thought this might be helpful to someone.