Subject: Delivery Status Notification (Failure)
From: "Mail Delivery Subsystem" <[email-masked]>
To: <[email-masked]>
Date: Thu, 13 Jul 2017 10:39:41 -0700 (PDT)

** Address not found **

Your message wasn't delivered to [email-masked] because the address couldn't be found. Check for typos or unnecessary spaces and try again.

The response from the remote server was:
550 5.1.1 Recipient address rejected: {Gateway