Microsoft's outlook.com / hotmail.com / msn.com / live.com email service features spam controls that have been known to occasionally block legitimate senders. When this happens, you may recieve a non-delivery report (NDR, aka bounce message) that looks something like this:
----- The following addresses had permanent fatal errors -----
(reason: 550 5.7.1 Unfortunately, messages from [18.104.22.168] weren't sent. Please contact your Internet service provider since part of their network is on our block list (S3140). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [DM6NAM12FT056.eop-nam12.prod.protection.outlook.com] Reporting-MTA: dns; your.email.server
If this happens to you, here are steps that you can take to receive support from them and ultimately have your IP address un-blocked.
- Fill out the form in its entirety and submit it here: http://go.microsoft.com/fwlink/?LinkID=614866 Be sure to provide an accurate email address where you can be reached.
- Microsoft will send an automated response that they are looking into the issue. Please be patient when waiting for this, as it may take several minutes or even hours to process.
- Microsoft will send a more targeted response sometime after that, usually within 24-48 hours. In some cases this will result in you being notified that they're going to fix (or "mitigate") the issue. However, many cases involve additional steps.
You may hear that your issue does not qualify for mitigation, with suggestions on changes to make to your email system. While those suggestions are valid and may be worth reviewing, this response does not result in your immediate issue being resolved. In that case, continue on.
- Reply to that email stating that the error still exists and you need further assistance to solve the problem. You might add that this is causing difficulty in communicating with your mutual customers (ie: those you share with Microsoft.) Be polite and businesslike while keeping your request short and to the point.
- Some time after that you will likely receive a response that your issue is very important and they will be looking into by the Escalations Team. Sometime later, you should receive a response from the "Deliverability Support Team" that the issue is fixed, or that they need something further from you. Continue pursuing assistance as needed via the ticket. Or if your issue has been resolved then you should be able to send email to their system once again.
Microsoft continues to maintain the importance of their Junk Mail Reporting Program (JMRP) and Smart Network Data Services program (SNDS). If these programs are a good fit for your operations, we encourage you to enroll.
Please note that this information is provided on a best-effort basis using experience from cases we have assisted with. As we maintain no control over Microsoft and their policies, we are unable to guarantee specific results in all cases. As always, we highly recommend that you maintain your email sending systems with best-practices in mind, and we require all of our customers to adhere to our Acceptable Use Policy which prevents the sending of spam and unsolicited bulk email.