The programmers met a problem when use Typo3, the clients can’t login with IE but can login with Firefox/Opera.
After the investigation , we find the problem is the cookies. Typo3 can set the domain for the cookies. change the setting to “.domain.com” it works.
btw, close the browers and clean the cookies the most right way.
In order to do this properly, remember to close your browser first. This is because all your cookies are held in memory until you close your browser. So, if you delete the file with your browser open, it will make a new file when you close it, and your cookies will be back.
Refer of the cookies.