Quote: "Although this page is encrypted, the information you have entered is to be sent over an unencrypted connection and could easily be read by a third party"

That is the "PostToInsecureFromSecureMessage" warning and can't be suppressed.
You will get that warning if you go from a secure https connection to an insecure http connection and POST data entered in a form on a secure site is send to an http server.

The warning tells you that you are sending data from a secure site to a non secure http url.

How do I fix this? I have been trying without success. I am brand new to Firefox, and have not faced this problem before. I tried adjusting my settings without success. Thanks.

How do I fix this security warning ?

There is nothing for you to fix, it has to be fixed on the website you are connecting with. Other web browsers might not give you that type of alert, but it is due a website starting out with a secure connection and then allowing data to be transmitted by an un-secure connection after you are logged in.

That can be a big deal is you are using a wireless connection to the internet, someone sitting close by can "snoop" on your connection if it isn't encrypted. A lot harder to "snoop" when you're using a wired connection (plus, more laws are broken when "intercepting" on a wired connection).

I have never seen that with a financial institution's website, but it is common with web mail portals and some company's intranet websites. What type of websites are you seeing that with?

I recently started using Mozilla Firefox, due to increasing problems with Internet Explorer. I have MSN as my homepage setting, and the security warning pops up when I go to my MSN homepage. This never happened before using Firefox. I don't know what to do next??? Thank you very much!

Yes please provide a way to disable this message. It is absolutely ridiculous that you can't turn this off. I understand trying to keep the sheep safe, but at least give us a technical workaround for those that are stuck with poorly designed websites that we have to use everyday. I have users that 60+ years old, any popup at all and they freak out. I have set all security warnings in about:config to false yet I still get this message. If you aren't going to provide a way to disable it, then give me a trusted site list where I can add sites I know are good. This gives us the best of both worlds. You can still play herder for the sheep and websites that we know are good and have to access we can add to the trusted sites list. Honestly, this is a regression in functionality. Firefox used to be good.