I saw your additional note: "I have cleared cache and cookies. Refreshed Firefox. Disabled extensions. Nothing is working"

You might need to use Microsoft Edge or another browser for now. If you could report this to Intuit Support, that would be helpful so they can test and let you know whether their site is incompatible with Firefox, or it's something specific to your browser.

I have reported this to Intuit, who in turn told me to report it to Firefox/Mozilla. I have been using Firefox all the years with Intuit, only since Friday afternoon have i been experiencing this issue

Firefox's "Total Cookie Protection" feature limits how sites can use "third party" or "cross-site" cookies, meaning cookies from different websites than the one you see in the address bar. Some sites pass you back and forth between different servers during login because they have their services spread out over a number of different servers. In those cases, you might be able to submit a form successfully on one page and then the next page says you are not logged in. Frustrating!

You can make exceptions to this feature when needed (for each server that you visit as part of the process of using this company's services). More info in the following articles:

• Introducing Total Cookie Protection in Standard Mode
• Total Cookie Protection and website breakage FAQ

Any difference?

Good morning

I disabled Total Cookie Protection and i received the error message as before.