Mail delivery system

Bonjour,

Ma config :
Windows XP
Outlook express 6.0

Depuis hier, suite à l'envoi d'email vers des destinataires hotmail, je reçois un e mail d'erreur suivant :
This is the mail system at host msfrf2122.sfr.fr.

" I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

The mail system

<xxx@xxx.com>: host mx2.hotmail.com[65.55.92.168] said: 550
SC-002 Mail rejected by Windows Live Hotmail for policy reasons. The mail
server IP connecting to Windows Live Hotmail has exhibited namespace mining
behavior. If you are not an email/network admin please contact your
E-mail/Internet Service Provider for help. Email/network admins, please
visit https://sendersupport.olc.protection.outlook.com/pm/ for email delivery information and support
(in reply to MAIL FROM command)"


Bien entendu mes correspondants ne reçoivent pas mes emails.
Mon fournisseur d'accès est neuf/sfr,, mais mon adresse en tant qu'expéditeur est une adresse @wanadoo.fr

Mes paramètres pop et smtp sont les suivants :
Courrier entrant : pop.orange.fr
Courrier sortant : smtp.neuf.fr