554 5.7.1 错误含义

liujun1071

我这边有个用户给Citibank发信时，有时被退信，内容如下：<br>
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undeliverable to user@citigroup.com<br>
Original message follows.<br>
Received: from TESTpor055bei[222.64.145.36]by mail.test.com with ESMTP(SMTPD32-8.05) id AEDD5D0132;<br>
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我查了一下日志，有下面错误，但没查到具体含义和解决方案，不知大家见过没有？<br>
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554 5.7.1 Appears to be spam (qid: j4J1i9M8019836, SPF: 0), caught on imbaspam-ny09<br>
ERR undeliverable 554 5.7.1 Appears to be spam (qid: j4J1i9M8019836, SPF: 0), caught on imbaspam-ny09<br>
SMTP_DELIV_FAILED

liujun1071

经过分析，我觉得是Citibank Mail spam系统过滤导致的，可能信中存在某些出发过滤的原因。