zammad/test/data/mail/mail063.yml

--- !ruby/hash:ActiveSupport::HashWithIndifferentAccess
from: MAILER-DAEMON@mx1.example.com (Mail Delivery System)
from_email: MAILER-DAEMON@mx1.example.com
from_display_name: Mail Delivery System
subject: Undelivered Mail Returned to Sender
content_type: text/plain
body: |
  This is the mail system at host mx1.example.com.

  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.

                     The mail system

  <notextisting@example.com>: user unknown