Content-Type: text/plain; charset=utf-8
Subject: Delivery failure, user's mailbox is full

Hi,
  I am sorry to tell you that %(rcpt)'s mailbox is full, we cannot
deliver any message into this mailbox, please try it later.

Below is the original mail information:
   Time:    %(time)
   From:    %(from)
   To:      %(rcpts)
   Subject: %(subject)
   Parts:   %(parts)
   Length:  %(length)
