不能寄信(550 #5.1.0 Address rejected) - Google

最近用gmail時發現有幾封不能寄，

是顯示：

Delivery to the following recipient failed permanently:

****@********.tw

Technical details of permanent failure:
Google tried to deliver your message, but it was rejected by the server for
the recipient domain *******.com.tw by parmail1.fr.publicisgroupe.net.
[81.200.177.120].

The error that the other server returned was:
550 #5.1.0 Address rejected.

我查了一下是SMTP Error，

不過我不了解這是什麼；

也有說是對方將我加入黑名單，

但我不是寄廣告信，之前也沒發過信給她，

但我不知如何修改，請問要怎樣才能寄信．

謝謝^^

--