probleme d'envoi avec outlook

bonjour a tous
voici le mail que je recois lorsque j'envoi des mail a certaine personne merci de m'aide



Failed to deliver to ''natacha-69800@hotmail.fr''
SMTP module(domain @212.247.154.44:hotmail.fr') reports:
host name is unknown


Received: from [83.179.145.26] (HELO nomd4vt2huy1ma)
by mailfe02.swip.net (CommuniGate Pro SMTP 5.0.8)
with SMTP id 188880762; Fri, 28 Apr 2006 11:21:30 +0200
Message-ID: <001601c66aa5$22c39930$0301a8c0@nomd4vt2huy1ma>
From: "severine veyrat" <sev.v@tele2.fr>
To: <'natacha-69800@hotmail.fr'>
Cc: "severine" <sev.v@tele2.fr>
Subject:
Date: Fri, 28 Apr 2006 11:21:27 +0200
MIME-Version: 1.0
Content-Type: multipart/mixed;
boundary="----=_NextPart_000_0012_01C66AB5.E414EFC0"
X-Priority: 3
X-MSMail-Priority: Normal
X-Mailer: Microsoft Outlook Express 6.00.2800.1506
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1506