메일서버를 설치했는데요...

The original message was received at Tue, 3 Nov 2009 19:20:37 +0900
from smtp6.nate.com [203.226.253.216]

----- The following addresses had permanent fatal errors -----
<seoclub@mail.fireworks.pe.kr>
(reason: 553 5.3.5 system config error)

----- Transcript of session follows -----
553 5.3.5 mail.fireworks.pe.kr. config error: mail loops back to me (MX problem?)
554 5.3.5 Local configuration error

다른곳에서 메일을 보내면 이런내용의 메일이 돌아옴니다;;

무슨 말인지 모르겠어요;;;