内部信都被退了

lzz

同事在美国，现在发过来的内部信件都被退了，请救命啊！！！
以下是退信的内容：
This is the Symantec Mail Security program at host mail.globalsuite.net.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to <postmaster>

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                        The Symantec Mail Security program

<xxxx@wellsco-group.com>: host mail.wellsco-group.com[211.155.224.42]
    said: 536 authentication failed. (in reply to MAIL FROM command)

Reporting-MTA: dns; mail.globalsuite.net
X-Symantec-Mail-Security-Queue-ID: 1CA7C9B0300
X-Symantec-Mail-Security-Sender: rfc822; yyy@wellsco-group.com
Arrival-Date: Tue, 29 Apr 2008 02:20:49 -0600 (MDT)

Final-Recipient: rfc822; xxxx@wellsco-group.com
Action: failed
Status: 5.0.0
Diagnostic-Code: X-Symantec-Mail-Security; host
    mail.wellsco-group.com[211.155.224.42] said: 536 authentication failed. (in
    reply to MAIL FROM command)

请高手帮忙分析下原因。。。

rayer

536 authentication failed这个错在http://www.winwebmail.com/spam.html上有说