샌드메일 받는것이 안됩니다

반송된 에러메세지 입니다. 어떻게 해야하는지...

The original message was received at Mon, 6 Sep 2004 15:11:47 +0900
from [211.233.31.195]

----- The following addresses had permanent fatal errors -----
<ko@mi.com>

----- Transcript of session follows -----
<ko@mi.com>... Deferred: Connection refused by ns.xxxxx.net.
Message could not be delivered for 1 hour
Message will be deleted from queue

Reporting-MTA: dns; smail-105.hanmail.net
Arrival-Date: Mon, 6 Sep 2004 15:11:47 +0900

Final-Recipient: RFC822; ko@mi.com
Action: failed
Status: 4.4.7
Remote-MTA: DNS; ns.xxxxx.net
Last-Attempt-Date: Mon, 6 Sep 2004 16:17:05 +0900