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Emails from our IP are rejected by Hotmail/Outlook.com – IP not listed on delisting portal

Bravo Kwambo 20 Reputation points
2025-09-14T11:47:12.79+00:00

Hello,

We are experiencing issues when sending emails from our mail server to Hotmail/Outlook.com addresses. The emails are being rejected, and we suspect our sending IP might be blocked.

However, when we check the IP address on the Office 365 Anti-Spam IP Delist Portal, it says the IP is not currently blocked in their system.

✅ We have verified the following:

  • SPF record is correctly configured
  • DKIM is enabled
  • DMARC is in place
  • Reverse DNS (PTR) is set properly

We would appreciate assistance from Microsoft to verify if our IP is blocked and to help us resolve this issue.

📌 Sending IP: 41.190.233.124

Thank you in advance!

Exchange | Exchange Server | Other
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Accepted answer
  1. Austin-H 4,390 Reputation points Microsoft External Staff Moderator
    2025-09-14T14:22:36.5266667+00:00

    Hi @Bravo Kwambo
    Thank you for posting question to Microsoft Q&A.

    According to this issue, may I know if you are using Microsoft Exchange as your email service provider? If that is the scenario, then please help us to raise the ticket via Microsoft 365 Admin Center.

    User's image

    As Microsoft Q&A is a public forum - and we are moderators who do not have access to Microsoft Internal system so we could not assist you in investigating specified domain. Raising ticket directly to Microsoft Support Team is recommended.

    You could also raise the ticket via personal Microsoft support channel (with personal Microsoft account which is Hotmail/Outlook.com) via this link: https://support.microsoft.com/en-us/home/contact?SourceApp=smc2&ContactUsExperienceEntryPointAssetId=S.HP.SMC-HOME (make sure you are logged in with personal Microsoft account).

    I truly hope that you will have your issue resolved as soon as possible.

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".   

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  1. Bravo Kwambo 20 Reputation points
    2025-09-14T14:50:14.3733333+00:00

    Hi, thanks for your reply.

    Yes, we are using Microsoft Exchange Server as our email system.

    However, we do not currently have an active support plan in Microsoft 365 Admin Center, which prevents us from opening a support ticket via that portal.

    Our emails to Hotmail/Outlook.com addresses are being rejected with error S3140, and the IP address (41.190.233.124) is not listed on the Office 365 IP delist portal.

    Could you please escalate this or advise on how to proceed to request delisting of this IP?

    Thanks in advance.

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