邮件发出总是退回,提示SMTP error, RCPT TO: 550

pc138

退信内容如下:

你发送到Sabine.Gaiser-Jetter@sanetta.de的邮件由于以下原因被退回 : SMTP
error, RCPT TO: 550-Callback setup failed while verifying
<XXX@lycotex.com>
550-Called:   202.109.249.14
550-Sent:     MAIL FROM:<>
550-Response: 553 Requested action not taken: NULL sender is not allowed
550-The initial connection, or a HELO or MAIL FROM:<> command was
550-rejected. Refusing MAIL FROM:<> does not help fight spam, disregards
550-RFC requirements, and stops you from receiving standard bounce
550-messages. This host does not accept mail from domains whose servers
550-refuse bounces.
550-Sender verification failed (Sending test bounce to XXX@lycotex.com
550 failed).

1、对方邮件地址无误，为德国邮件地址，并可接收对方发来的信件
2、国内、香港邮件收发都无误
3、是企业邮局更改MX地址后出现的问题，联系邮局提供商，对方称为国外的反垃圾邮件屏蔽了。

望有类似解决方法的达人回复。
也望有相同经历的同仁发表意见！

谢谢！

钉子

１．有被反垃圾邮件策略阻止的可能．
２．也有GFW的可能．