특정계정에서 baddnsconfig 에러 발생

안녕하세요.

최근에 hanmail.net 으로 메일을 보낼라치면, BadDnsConfig 에러가 나면서 메일전송이 안되다가,,

(가끔씩은 또 되구요..) daum.net으로 보내면 전송이 되는데,,

이거 혹시 왜그러는지 아시는 분 계신가요?

아래는 리턴메일내용입니다. 답변 달아주심 정말 감사~~

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This Message was undeliverable due to the following reason:

Your message was not delivered because the Domain Name System
(DNS) for the destination computer is not configured correctly.
The following is a list of reasons why this error message could
have been generated.  If you do not understand the explanations
listed here, please contact your system administrator for help.

      - The host does not have any mail exchanger (MX) or
        address (A) records in the DNS.

      - The host has valid MX records, but none of the mail
        exchangers listed have valid A records.

      - There was a transient error with the DNS that caused
        one of the above to appear to be true.

You may want to try sending your message again to see if the
problem was only temporary.

     DNS for host hanmail.net is mis-configured
The following recipients did not receive this message:
     <xxxxxxx@hanmail.net>

Please reply to <postmaster@xxxxxx.com>
if you feel this message to be in error.