我的自建mailcow向hotmail邮箱发送一直被退回

Question

问题，一直被退回：

This is the mail system at host mail.lmarkglobal.com.

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

******@hotmail.com: host

    hotmail-com.olc.protection.outlook.com[52.101.10.7] said: 550 5.7.1

    Unfortunately, messages from [52.221.122.98] weren't sent. Please contact

    your Internet service provider since part of their network is on our block

    list (S3140). You can also refer your provider to

http://mail.live.com/mail/troubleshooting.aspx#errors. [Name=Protocol

    Filter Agent][AGT=PFA][MxId=11BBBEFDCB2EAAC7]

    [BN3PEPF0000B06E.namprd21.prod.outlook.com 2025-08-20T08:31:13.341Z

    08DDDF7EE5D80048] (in reply to MAIL FROM command)

已经申诉：

Support request number: 7084744827

请帮忙加速

Answer 1

550 5.7.1代表发件方被Outlook.com后端列入封锁清单了。需要你填表单申请delist. portal及步骤请参考那份Outlook邮箱的经验文档，如下面的注释/评论帖。