题目

This is the Postfix program at host bjd.com.cn.
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
If you do so,please include this problem report.You can
delete your own text from the message returned below.
The Postfix program
:user unknown.Command output:/usr/local/bin/maildrop:
Invalid user specified.

提问时间：2020-10-13

答案