This is the Postfix program at host www.mobile-ip.de. I'm sorry to have to inform you that the message returned below could not be delivered to one or more destinations. For further assistance, please send mail to <postmaster> If you do so, please include this problem report. You can delete your own text from the message returned below. The Postfix program &lt;sean.figgins(a)iptel.org&gt;rg>: host fox.iptel.org[195.37.77.101] said: 550 &lt;sean.figgins(a)iptel.org&gt;rg>: User unknown in virtual alias table