Content-Type: text/plain; format=flowed
Subject: Delivery failure, mail system error!
From: "Mail Daemon"<postmaster@system>

Hi,
  I am sorry to tell you that some error occurs in our mail system, your message to "<rcpt>" cannot be delivered, please contact our mail system administrator to settle this problem. Thank you!

Below is the original mail information:
   Time:    <time>
   From:    <from>
   To:      <rcpts>
   Subject: <subject>
   Parts:   <parts>
   Length:  <length>
