I think I have found a corelation with the enhanced security that IE is applying by itself on several Web sites. For .NET applications that use a cookie or any other Web sites that need the same, if a form is accessed in a page which contains a HTML password textbox field, and that there are several submits done on that form in a short time, which would be the case when someone makes several attemps to log in, IE would block the cookie to that site.

Then, the operation to add the site into the list of trusted sites by going into Tools/Internet Options/Security/Trusted Sites/Sites and adding the site it, restarting the browser and logging in again would work.

This is something that has frustrated me since a while. This automatic enhance in the security is causing a lot of problems. It took me a while to find this corelation. I had this situation on my laptop a month ago and from a client's site. On both occasions, I mixed up the typing which has resulted in several submissions of a form containing a textbox password field, and this has caused this security to be added.

I would like to know if someone else already went into that situation, heard about it or have found something close to that.