HTTP authentication problem

Hi,I am fighting the following problem: Domino Web Access works fine from the Internet, but I am unable to authenticate users with their HTTP password from the intranet (LAN) anyway. It seems the redirect doesn’t work correctly, but I am not sure because I have got no error message in browser and either no at the console, the login redirect http://IPaddress/names.nsf?Login&RedirectTo=http://IPaddress/anyDB.nsf returns the login page every time. Thanks for any idea how to fix it.