對方寄信過來被退件Client host rejected: Adccess denied

最近客戶寄來的信件一直被退信,後來查詢Maillog發現
Mar 20 09:34:22 mail2 postfix/smtpd[4002]: NOQUEUE: reject: RCPT from mr.abc.com[220.130.XX.XX]: 554 5.7.1 <mr.abc.com[220.130.XX.XX]>: Client host rejected: Adccess denied; from=<user1@abc.com> to=<owner@kkk.com.tw> proto=ESMTP helo=<ot01.ttt.oa>

請問我在postfix上該要如何去設定才不會把客戶的信件rejected呢?
環境:
CentOS release 5.2 (Final)
Postfix 2.5.2
Mailscanner+spamassassin