winwebmail3.7.6.1版本21cn的邮箱发不了了?帮我看看

zj3721cn

很抱歉地通知您，邮件无法投递到指定收件人，请先通过其它方式向您的朋友发送信息，以免耽误。
请查看下面的退信原因：

> 日期: <Tue, 06 May 2008 09:18:06 +0800>
> 大小: <398>
> 动作: 失败

没有能够发送到以下的收件人:
<zj3721cn@21cn.com>

<<原邮件的正文及附件由于篇幅关系在这里省略了>>

服务器返回的技术细节:

<zj3721cn@21cn.com>: host 127.0.0.1[127.0.0.1] said: 550 bounce as<too many
    mails in the destination mailbox zj3721cn@21cn.com> (in reply to end of
    DATA command)  这是什么意思呀,大侠帮我分析下,老退信

zj3721cn

这是新浪的退信
This is the mail system at host mx3-28.sinamail.sina.com.cn.

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 mail system

<zj3721cn@mail3-79.sinamail.sina.com.cn>: host
    mail3-79i.sinamail.sina.com.cn[10.55.2.79] said: 522 5.2.2 can not find the
    user path (in reply to end of DATA command)