DSN: failed (Good day)

This is a Delivery Status Notification (DSN).

I was unable to deliver your message to
marco.huggenberger@gmail.com.

I said 
  (end of message)

And they gave me the error;
  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/answer/6590 to review our message
  552 5.7.0 content and attachment content guidelines. om4si50824704pdb.237 - gsmtp

 
Received: from lists.freedesktop.org ([151.42.215.110]) by by-night.ch for <marco@by-night.ch>; 
Fri, 26 Jun 2015 07:56:05 -0700
From: libreoffice@lists.freedesktop.org
To: marco@by-night.ch
Subject: Good day
Date: Fri, 26 Jun 2015 16:56:08 +0200
MIME-Version: 1.0
Content-Type: multipart/mixed;
        boundary="----=_NextPart_000_0001_EC01F6FB.DBC6E0AD"
X-Priority: 3
X-MSMail-Priority: Normal