Somehow I applied Autofill options to all websites and it is interferring with creating a label in USPS. How do I get rid of it?

Question

I had found the Autofil area (can't remember exactly where I found it) and must have entered my own information. But now when I go on the USPS website, it Autofils my own information in the TO: section. Even though I take the information out, and put in the correct information, when I click to go to the next screen, it won't advance and goes back to telling me that there is an error on the page. I have already contacted their tech support, and they told me it is not a problem with their site. So it has to be the autofil function that is messing me up. But I can't figure out how to get back to the "cleared" state. Thanks for any help in advance.

Answer 1

K, thanks for the explanation. Appreciate knowing who is responsible for what. I think I will avoid the add-on with the 'dead' area. Sounds like more frustration.
I just want something SIMPLE without tons of forms to figure out and fields and how do I want this app applied in which situations. Too much complexity for daily use. I would have to hire a "techie" to work my way through that. I was dealing with the tech support on USPS for MONTHS before someone finally tried my account on their computer and discovered that the site worked, it was not my cache or cookies, for history that needed to be cleared. They told me to contact Firefox because there was an incompatibility issue. So that is what gave me the clue to start looking at what settings on my computer could be the culprit. Then I looked at what was happening and that gave me the clue that it was Autofil.
So I went in and cleared enough so that I could work the label for that day. But apparently, there was still a default there, because today I had the same problem, thereby causing my question on this site.
I never had this problem with the other Autofil design, because it only worked when I was on a site and chose to implement the function.
I just want some thing that simple again. Do you have any pull with app designers at Mozilla?