550 SC-001 outlook.com rejecting mail for policy reasons – How to remove your server from the blacklist!

This article was updated on 15/10/2015

Check if your IP is on a mailing blacklist using our blacklist checking service.

So just when you think the internet is this great place for a server admin, where any problem can be solved (more or less) you suddenly hit a brick wall and your world crumples around you… outlook/msn/outlook suddenly decides it does not like your server or your clients or your mail and in fact decides to block all emails to their server indiscriminately.

Yes there is no god!! Yes you will go grey, then go bald, then consider assassinating someone who works for Microsoft… Because as you look into the problem you end up on countless Microsoft troubleshooting guides and they all hint the same thing…



However calm down a little bit – grab a cup of coffee, or perhaps something stronger and follow these steps, there not that painful and hopefully it will get you off Microsoft's mail blacklist.


Was I blacklisted?

Unfortunately I found myself pondering the same thing for several hours as it was not made *very* obvious and Microsofts troubleshooting guides made it even more confusing, but if the return mail header has the below status code then, yes you are blacklisted:

host mx3.hotmail.com […]: 550 SC-001 … Unfortunately, messages from … weren't sent. Please contact your Internet service provider since part of their network is on our block list. You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors.


You can check which blacklists you are on using our blacklist checker.


 Why was I blacklisted?

The first thing you should really try and discover is why you were blacklisted. This is most definitely because someone or some thing has been sending spam through or from your server to MSN email accounts.

Be a real admin, in WHM you can check logs of all sent email from your server by going to Home >> Email >> Mail Delivery Reports.

Make sure there is no spam coming from your server or that there is problem with your mail software, as this could also cause you to be blacklisted by hotmail.


How to be removed from the blacklist?

To start the process of getting your server removed from the blacklist you will need to fill in hotmail’s blacklist form. You can find the form here.

You can also join the Junk Mail Reporting Program (JMRP).


Good luck, please let me know if you are having trouble and if this guide ultimately helped you out of the shit!

Author: Dean WilliamsI'm a Web Developer, Graphics Designer and Gamer, this is my personal site which provides PHP programming advice, hints and tips

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This article has been very useful for me. The block has been partially removed by Microsoft, so I'm still having some issues (they've limited the number of e-mails that come from my server). But it's a good starting point anyway. Now I need to investigate where this bad reputation of my e-mail server comes from. Thank you for the help!

This works.

Just did it today. Microsoft support replied in less than 24 hours:

"Our investigation has determined that the above IP(s) qualify for conditional mitigation. These IP(s) have been unblocked, but may be subject to low daily email limits until they have established a good reputation."

Not bad!

Wow, my server is on the block list, I have check my delivery report to find out that lots of spam email were actually originated from my server and this is due to partly having an unfinished website I was developing and I totally forgot about it. Basically pots trying to register and the pot will make up emails such as kdjfdlfjdkfjdkfj@hotmail so your server will be sending emails in tons. Also as a good measure enable DKIM and reject failure. also enable SPF. Thank you for this article, I was searching for the form and you have provided me… Read more »