Could not complete sender verify callout ?

000000yi

Tue 2007-01-16 17:00:54: Session 736; child 3
Tue 2007-01-16 16:59:38: Parsing Message <e:\mdaemon\queues\remote\retry\pd90000000389.msg>
Tue 2007-01-16 16:59:38: From: xxx@xxx.com.cn
Tue 2007-01-16 16:59:38: To: xxx@xxx.com
Tue 2007-01-16 16:59:38: Subject: =?gb2312?B?y83Ym4bO?=
Tue 2007-01-16 16:59:38: Message-ID: <001c01c7390a$13f02570$7000a8c0@xxx02>
Tue 2007-01-16 16:59:38: Route slip host: xxx.com
Tue 2007-01-16 16:59:38: Route slip port: 25
Tue 2007-01-16 16:59:38: MX-record resolution of [xxx.com] in progress (DNS Server: 61.177.7.1)...
Tue 2007-01-16 16:59:38: * P=000 D=xxx.com TTL=(60) MX=[xxx.com] {xx.xx.30.194}
Tue 2007-01-16 16:59:38: Attempting MX: P=000 D=xxx.com TTL=(60) MX=[xxx.com] {xx.xx.30.194}
Tue 2007-01-16 16:59:38: Attempting SMTP connection to [xx.xx.30.194 : 25]
Tue 2007-01-16 16:59:38: Waiting for socket connection...
Tue 2007-01-16 16:59:39: Socket connection established (192.168.0.110 : 1833 -> xx.xx.30.194 : 25)
Tue 2007-01-16 16:59:39: Waiting for protocol initiation...
Tue 2007-01-16 16:59:41: <-- 220-xxx.moref.com ESMTP Exim 4.63 #1 Tue, 16 Jan 2007 17:04:54 +0800
Tue 2007-01-16 16:59:41: <-- 220-We do not authorize the use of this system to transport unsolicited,
Tue 2007-01-16 16:59:41: <-- 220 and/or bulk e-mail.
Tue 2007-01-16 16:59:41: --> EHLO xxx.com.cn
Tue 2007-01-16 16:59:41: <-- 250-xxx.moref.com Hello xxx.com.cn [xx.x.xx.xxx]
Tue 2007-01-16 16:59:41: <-- 250-SIZE 52428800
Tue 2007-01-16 16:59:41: <-- 250-PIPELINING
Tue 2007-01-16 16:59:41: <-- 250-AUTH PLAIN LOGIN
Tue 2007-01-16 16:59:41: <-- 250-STARTTLS
Tue 2007-01-16 16:59:41: <-- 250 HELP
Tue 2007-01-16 16:59:41: --> MAIL From:<xxx@xxx.com.cn> SIZE=482470
Tue 2007-01-16 16:59:42: <-- 250 OK
Tue 2007-01-16 16:59:42: --> RCPT To:<xx.xx@xxx.com>
Tue 2007-01-16 17:00:22: <-- 451 Could not complete sender verify callout
Tue 2007-01-16 17:00:22: --> RCPT To:<xx.xx@xxx.com>
Tue 2007-01-16 17:00:54: <-- 451 Could not complete sender verify callout
Tue 2007-01-16 17:00:54: --> QUIT
Tue 2007-01-16 17:00:54: <-- 221 snake.moref.com closing connection
Tue 2007-01-16 17:00:54: This message is 0 days old; it has 1 days left to get delivered
Tue 2007-01-16 17:00:54: SMTP session terminated (Bytes in/out: 453/152)