outlook domain is blocking our messages ... recent change of public ip

Syed Afsar 0 Reputation points
2023-12-29T12:26:12.5166667+00:00

CO1NAM11FT096.mail.protection.outlook.com gave this error: Unfortunately, messages from [xx.xx.xx..xx] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [CO1NAM11FT096.eop-nam11.prod.protection.outlook.com 2023-12-29T00:04:05.337Z 08DC07928637784E]

i am using exchange server 2019 on premises when we send messages to outlook domain we are getting the above message

i request microsoft to delist my ip from being blocked as we have recently changed our public ip

Exchange Server
Exchange Server
A family of Microsoft client/server messaging and collaboration software.
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  1. Yuki Sun-MSFT 41,216 Reputation points Microsoft Vendor
    2024-01-01T02:05:12.56+00:00

    Hi @Syed Afsar ,

    i am using exchange server 2019 on premises when we send messages to outlook domain we are getting the above message

    By "Outlook domain", do you mean outlook.com or hotmail.com accounts? If this is the case, based on my research, it's recommended to read this FAQ first and the delisting form for Outlook.com, the consumer service can be found via this link: https://support.microsoft.com/supportrequestform/8ad563e3-288e-2a61-8122-3ba03d6b8d75.

    If you also have the issue sending mails to recipients whose email address are in Microsoft 365, you can use the delist portal (https://sender.office.com/) to remove yourself from the blocked senders list.

    Reference: External senders - Use the delist portal to remove yourself from the blocked senders list and address 5.7.511 Access denied errors.


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