title: Undelivered Mail Returned to Sender
body: <p>Just wondering if there is any way to change the mail subject "Undelivered Mail Returned to Sender" to something else, if the error code is 550.</p>
  
  <p>If no then is there is any way to detect a correct email.I am not saying about the email validation.That part is ok.But sometimes if there is no mail box then we get 550 error code.</p>
  
  <p>Thanks,</p>