Hi,

from a few hours, i'm not able to send email from outlook.com to a specific domain.
Using web interface, the recipient is highlighted in a red box with a description "the address may not be valid"
If i send the mail, after few seconds i receive the notification error:

"Reporting-MTA: dns;dub0-omc4-s2.dub0.hotmail.com
Received-From-MTA: dns;DUB124-W37
Arrival-Date: Mon, 7 Oct 2013 00:25:31 -0700

Final-Recipient: rfc822;  <recipient address>
Action: failed
Status: 5.5.0
Diagnostic-Code: smtp;554 The mail could not be delivered to the recipient because the domain is not reachable. Please check the domain and try again (1479978268:301:-2147467259)
"

I've already been in contact with the support of the recipient domain, and they said that it's an outlook.com issues since the ip addresses of the servers have poor reputation, and a delisting must be done.

what can i do ?

thanks in advance.
Dario.