How the heck do I stop firstname.lastname@example.org to send messages? I have a custoumer who has a phpgame on his site and it sends the user password with e-mail and i recive the error messages. About 20 -30 a day the errormessage is i don´t show the usernames : This message was created automatically by mail delivery software (Exim). A message that you sent could not be delivered to one or more of its recipients. This is a permanent error. The following address(es) failed: &email@example.com SMTP error from remote mailer after RCPT TO:&firstname.lastname@example.org&: host mx1.hotmail.com [18.104.22.168]: 550 Requested action not taken: mailbox unavailable ------ This is a copy of the message, including all the headers. ------ Return-path: &email@example.com& Received: from nobody by server2.nethotell.org with local (Exim 3.36 #1) id 18GjO5-0004K0-00 for &firstname.lastname@example.org; Tue, 26 Nov 2002 18:20:41 +0100 Now I have a new custoumer who has a sales site using PHP and it´s the same error. It is not only for hotmail users. I have checked that the host hasn´t blocked server or domain. I have reversed dns and so on. But it will not work. I really need some help!