Domain not resolved

Hi, I would like to know why I keep getting this error message when I try to send e-mail.

This message was created automatically by mail delivery software.
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admin@theconversion.net Domain Not Resolved

Received:from mail.zoho.com by mx.zohomail.com
with SMTP id 1380507839150128.58912156122358; Sun, 29 Sep 2013 19:23:59 -0700 (PDT)
Message-ID:<1416cadea7a.1146721524271146178.-5772928175073015889@zoho.com>
Date:Mon, 30 Sep 2013 09:23:59 +0700
From:togaptartius <togaptartius@zoho.com>
User-Agent:Zoho Mail
To:<admin@theconversion.net>
Subject:Tes
Content-Type:multipart/alternative;
boundary="----=_Part_378184_1941490227.1380507839097"

Thanks