[Wlug] qmail Problem! - Can only take my mail if sent using qmail-inject,.....

Hi all, I'm still got a serious problem with my qmail server. Now, I can send email to my address using qmail-inject directly from my console. Then, I'll try to retreive my email from my Outlook, it works, I can get my my mail, but it is said form my MAILER-DAEMON. In other case, I can send using my email address that listed in my qmail server successfully, but If some body send me message, I could not get it, in fact, the sender doesnt get the confirmation that the email has sent to invalid username in the defined domain. It means that I can receive the email, but where the email saved ? what configuration that I've got to do to fix this ? Thanks Men.