I can view the website with no problems so I do not think it is objecting to the Firefox version. This forum is picking up your User Agent String, and that seems to be correct - something that causes problems on some sites when it is incorrect.

Please try overriding the cache for that site by using keyboard shortcut Ctrl+F5 whilst on that site, and also clear the cookies for that site.

• Clear cookies and site data in Firefox_delete-cookies-for-a-single-site

It seems odd they even warn about viewing the site with an outdated browser. They even offer an insecure site version themselves. It is not as if you are interacting with the site and paying money or logging in.

• Not Secure http://www.cdc.gov/
• Secure https://www.cdc.gov/

I thought it odd also. I just thought it best to inform you guys in case there was something new going on.

Also, I was going to a page on the site from a link in a word document I'd saved (researching a specific illness). The age of the link was probably the problem in spite of the fact the link is still good.

Thank you for your time.