Outlook blocked my business email address

    Outlook has blocked my business email address which I do not use to send any sort of spam. I have a dedicated server and have had the same IP address for over an year. My emails pass the DKIM, SPF and DMARC test. MXToolbox says that this IP is not present in any blacklist. I have not sent any spam, automated or cold mails. This email is strictly used for business activities i.e. manually replying to emails from customers.

    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 (S3140).

    I am trying to get this email unblocked as per the guidelines provided by Microsoft’s support forum. Although its not a big concern because very few of my contacts use outlook. I do not want to change my server’s IP address just for Outlook.

    Message to Outlook

    Since my IP or mails have nothing wrong. It could be that you have placed my ISP in a blocklist. Please do not block ISPs. What do you have a spam folder for? If you believe email from an IP doesn’t have reputation enough to land in your INBOX, please send it to spam and place the email behind a red color warning page with a scary danger icon and a READ AT OWN RISK button. But please let people read the email if they wish to. Why would you reject a mail server that rarely connects to you? Please intelligently rate limit abusive mail-servers while letting the non abusive ones to connect.

    Progress so far

    I am waiting for response from Outlook after having submitted the Outlook Deliverability Support form. I’ll be adding information here once they reply regarding my issue.

    Reply from Outlook: Our investigation has determined that the above IP(s) do not qualify for mitigation.


    Change your IP if this happens to you as well. There’s no way to fix it when its not your fault.

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