Replied Issue sending emails to Microsoft related email addresses

[chriswiseman]

Just sent out my first low level email campaign and all live, outlook and hotmail emails soft bounced with teh following message:

Bounce Message:smtp;550 5.7.1 Unfortunately, messages from [103.79.1.10] 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. [Name=Protocol Filter Agent][AGT=PFA][MxId=11BD8819F349A7B3] [AMS0EPF000001A8.eurprd05.prod.outlook.com 2026-06-10T19:57:44.304Z 08DEC40CFEDDF057]|

How can i resolve this please?

 

[ArshilAhmad]

Hi @chriswiseman,

We have forwarded your concern to our technical team. Please allow us some time to investigate this issue. We will get back to you with an update as soon.

Thanks & Regards,
Arshil Ahmad
Customer Support Associate
Pabbly.com

 

[chriswiseman]

Thank You

 

[Preeti Paryani]

Hi @chriswiseman,

Thank you for your patience.

As per the latest update received from our technical team, it appears that one of our sending IPs is currently being blocked by Microsoft's mail servers. This is causing emails sent to Microsoft-related email addresses (such as Outlook, Hotmail, and Live) to bounce with the error you shared.

Our team is already in continuous communication with Microsoft's team regarding this matter and is actively working to get the affected IP whitelisted.

As soon as the IP is removed from the block list or we receive any further updates from our team, we will get back to you immediately.

We appreciate your understanding and patience while this is being resolved.