any idea? the zimbra network already include all 192.168.0.0/16 and 127.0.0.1

Oct 10 11:41:11 zim01 postfix/smtps/smtpd[7263]: Anonymous TLS connection established from mail1.zimbra..com[192.168.1.88]: SSLv3 with cipher RC4-MD5 (128/128 bits)
Oct 10 11:41:11 zim01 postfix/smtps/smtpd[7263]: NOQUEUE: reject: RCPT from mail1.zimbra.com[192.168.1.88]: 554 5.7.1 <test@us.zimbra.com>: Recipient address rejected: Access denied; from=<admin@zimbra.com> to=<test@us.zimbra.com> proto=ESMTP helo=<mail1.zimbra.com>