MD7.01发送到SINA很多次都不能发送成功，同样我用WEBEASYMAIL做服务器的话就可以发送成功，这是什么原因？
MD记录如下:
Tue 2004-04-20 12:56:14: From: zhoujunqi@corun.com
Tue 2004-04-20 12:56:14: To: zhoujunqi2000@sina.com.cn
Tue 2004-04-20 12:56:14: Subject: test
Tue 2004-04-20 12:56:14: Message-ID:
Tue 2004-04-20 12:56:14: MX-record resolution of [sina.com.cn] in progress (DNS Server: 202.103.86.3)...
Tue 2004-04-20 12:56:14: P=010 D=sina.com.cn TTL=(1) MX=[sinamx.sina.com.cn] {202.106.182.168}
Tue 2004-04-20 12:56:14: Attempting MX: P=010 D=sina.com.cn TTL=(1) MX=[sinamx.sina.com.cn] {202.106.182.168}
Tue 2004-04-20 12:56:14: Attempting SMTP connection to [202.106.182.168 : 25]
Tue 2004-04-20 12:56:14: Waiting for socket connection...
Tue 2004-04-20 12:56:14: Socket connection established (220.168.134.2 : 4014 -> 202.106.182.168 : 25)
Tue 2004-04-20 12:56:14: Waiting for protocol initiation...
Tue 2004-04-20 12:56:15: <-- 220 sina.com ESMTP
Tue 2004-04-20 12:56:15: --> EHLO corun.com
Tue 2004-04-20 12:56:15: <-- 250-sina.com
Tue 2004-04-20 12:56:15: <-- 250-PIPELINING
Tue 2004-04-20 12:56:15: <-- 250 8BITMIME
Tue 2004-04-20 12:56:15: --> MAIL From:
Tue 2004-04-20 12:56:15: <-- 250 ok
Tue 2004-04-20 12:56:15: --> RCPT To:
Tue 2004-04-20 12:56:15: <-- 250 ok
Tue 2004-04-20 12:56:15: --> DATA
Tue 2004-04-20 12:56:15: <-- 354 请继续 - go ahead
Tue 2004-04-20 12:56:15: Sending to [202.106.182.168]
Tue 2004-04-20 12:56:15: Transfer Complete.
Tue 2004-04-20 13:06:15: Connection timed out!
Tue 2004-04-20 13:06:15: This message is 0 days old; it has 5 days left to get delivered
Tue 2004-04-20 13:06:15: SMTP session abnormally terminated (Bytes in/out: 149/992)
Tue 2004-04-20 13:06:15: ----------

sina邮件服务器的问题，发送到sina的免费邮箱，成功与失败的比例差不多，