PHP Auth problem

Hi all I have a rather strange problem with php auth: i want to authenticate a user through php and validate it through imap_open function (to access his email). I send WWW-Authenticate header like this: header("WWW-Authenticate: Basic Realm=\"Private\""); After, i check for isset($PHP_AUTH_USER) and validate it through PHP. Can anyone tell me why, for a real user (it really exists), the authentication simply fails and asks me again for a username and password, without even leaving the authenticate intrinsic routine (the script just keeps telling me that the auth is failed, but WITHOUT running imap_open or any other part of the script). Why is that? If anyone has the time and the understanding, i can post the code fragment. Thanks ------------------------- Alexandru SOFRONIE maxx@mail.tehnoton.com ------------------------- IT Software Dept. Omega-Tehnoton GROUP +40-93-670773 -------------------------