Subject: Mail delivery failed: returning message to sender
From: Mail Delivery System <[email-masked]>
To: [email-masked]
Date: Tue, 14 May 2019 21:37:56 +0530

This message was created automatically by mail delivery software.

A message that you sent could not be delivered to one or more of its
recipients. This is a permanent error. The following address(es) failed:

  [email-masked]
    (generated from [email-masked])
    SMTP error from remote mail server after end of data:
    host alt4.gmail-smtp-in.l.google.com [64.233.177.26]:
    552-5.7.0 This message was blocked because its content presents a potential
    552-5.7.0 security issue. Please visit
    552-5.7.0  https://support.google.com/mail/?p=BlockedMessage to review our
    552 5.7.0 message content and attachment content guidelines. v17si780414ybs.363 - gsmtp