qmail 발송 에러입니다.

qmail + vpopmail + mysql을 설치하였습니다.

telnet 25로 접속해서 메일을 발송하면 정상적으로 발송되지 않습니다.
아래와 같은 메세지가 기록됩니다.

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Delivered-To: jindol2k@mail.sangman.com
Received: (qmail 6326 invoked for bounce); 24 Jul 2007 14:31:50 -0000
Date: 24 Jul 2007 14:31:50 -0000
From: MAILER-DAEMON@mail.sangman.com
To: jindol2k@mail.sangman.com
Subject: failure notice

Hi. This is the qmail-send program at mail.sangman.com.
I'm afraid I wasn't able to deliver your message to the following addresses.
This is a permanent error; I've given up. Sorry it didn't work out.

: 211.218.150.34 failed after I sent the message. Remote host said: 550 No thanks. 1611018

--- Below this line is a copy of the message.

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Received: (qmail 6318 invoked from network); 24 Jul 2007 14:31:28 -0000
Received: from unknown (202.31.139.60)
by 0 with SMTP; 24 Jul 2007 14:31:28 -0000
Hi~!
OK!

그런데 메일을 받는것은 정상적으로 됩니다. 조언 부탁드립니다^^: