Content-Type: text/plain; format=flowed
Subject: Delivery failure, system has refused your mail because of some reason
From: "Mail Daemon"<postmaster@system>

Hi,
  your message to "<rcpt>" has been be refused by some reason!

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