英语翻译This is the mail system at host mail3-20.sinamail.sina.c

英语翻译
This is the mail system at host mail3-20.sinamail.sina.com.cn.
I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.
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 attached returned message.
谁能告诉我 这是什么意思