J'ai le même problème. Impossible d'envoyer des emails vers les boîtes hotmail.
Objet en retour: Mail Delivery Failure
This message was created automatically by the mail system (ecelerity).
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:
>>> xxxxxx@hotmail.com (after MAIL FROM): 550 SC-001 (SNT0-MC4-F27) Unfortunately, messages from 195.186.99.123 weren't sent. Please contact your Internet service provider since part of their network is on our block list. You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors.