Undelivered Mail Returned to Sender

[Mail Delivery System]

This is the Postfix program at host 263commail.com.

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

<address@hidden>: user unknown. Command output:
    /usr/local/bin/maildrop: Invalid user specified.

Reporting-MTA: dns; 263commail.com
Arrival-Date: Fri,  6 Jun 2003 10:40:11 +0800 (CST)

Final-Recipient: rfc822; charlesliu@dayang.com.cn
Action: failed
Status: 5.0.0
Diagnostic-Code: X-Postfix; user unknown. Command output:
    /usr/local/bin/maildrop: Invalid user specified.

--- Begin Message --- Subject: Re: 45443-343556 Date: Fri, 6 Jun 2003 10:29:06 +0800

Please see the attached file.

"submited.pif
Description: Binary data

--- End Message ---