Emails being blocked

Question

Emails being blocked

Anonymous

I am getting this error when sending emails

Remote server replied: 550 5.7.1 Unfortunately, messages from [77.68.124.236] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3150)

I have contacted the ISP who contacted Microsoft but they replied with

Thanks for your patience while we investigated your request. Below your IP address(es) and their status(es) are listed.

Not qualified for mitigation

77.68.124.236;

That IP and the domains on there, there are 6, all have DKIM, SPF and DMARC setup correctly. MXToolbox does not show them on any block lists and they all send with SSL.

Can someone tell me why they are being blocked ?

Thanks

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1 answer

Answer 1

Hello Richie,

Welcome to the Microsoft Community.

I understand that you have been unable to send emails to Microsoft domains.

According to the error message, the IP address provided by your internet service provider may have a poor reputation.

This may not be caused by your usage, but possibly by previous users of your ISP. If users have engaged in inappropriate activities using their provided IP, it could lead to this situation. You can try filling out this form to restore the reputation. New support request (office.com). It seems your ISP has already filled out the form to resolve the issue, but it was not successful.

It is recommended that you directly contact your ISP to request an IP change. This is usually due to their insufficient user screening, which affects their users’ experience. Microsoft’s vision is to protect users from spam.

Please feel free to let me know if you need any further assistance.

Best Regards,

Zachary.W - MSFT | Microsoft Community Support Specialist

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Emails being blocked

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