用户收信提示 "User not local"而发信正常?

hshoe139

单位里一个用户ali@b.com接收sele@a.com发来的信件,偶尔能收到,偶尔收不到,日志如下:  (对方的退信内容reason: 551 User not local; please try )

接受 SMTP 连接来自 [60.200.3.4 ：1105]
--> 220 b.com ESMTP MDaemon 9.5.2; Fri, 16 May 2008 14:21:07 +0800
<-- EHLO mail.a.com
Performing IP lookup (mail.a.com)
*  D=mail.a.com TTL=(1440) A=[60.200.3.4]
---- End IP lookup results
--> 250-b.com Hello mail.a.com, pleased to meet you
--> 250-ETRN
--> 250-AUTH=LOGIN
--> 250-AUTH LOGIN CRAM-MD5
--> 250-8BITMIME
--> 250 SIZE 20000000
<-- MAIL From:<sele@a.com> SIZE=39834
Performing IP lookup (a.com)
*  D=a.com TTL=(1440) A=[60.200.3.4]
---- End IP lookup results
Performing SPF lookup (a.com / 60.200.3.4)
*  Result: none; no SPF record in DNS
---- End SPF results
--> 250 <sele@a.com>, Sender ok
<-- RCPT To:<ali@b.com>
--> 250 <ali@b.com>, Recipient ok
<--
--> 500 What? I don't understand that.
<-- .
--> 500 What? I don't understand that.
<-- QUIT
--> 221 See ya in cyberspace

我尝试的操作是关闭垃圾过滤,重建帐户,把对方的域名加入白名单.都无效
然而对方的邮件用户发给我方其他用户的信件都是正常收发的.

请高手指点,感谢ing

redif

邮箱本身有不有问题。。。。。。。。。。。。。。

[ 本帖最后由 redif 于 2008-5-19 08:44 编辑 ]

hshoe139

邮箱我都重建了?  这二天我关掉垃圾过滤好像就没发现问题了, 不知要怎么解决此问题?垃圾过滤白名单中我早就有加不能收信邮件地址了/