Microsoft's email service consists of hotmail.com, outlook.com, msn.com and live.com domains. As this is a very popular email service, you may eventually experience an issue within your server/network that resorts in you getting blocked by Microsoft due to undesirable email habits. This could be due a number of things.

Ex:

• Spamming
• Unsolicited newsletters
• No opt-out subscription for newsletters
• Suspicious email patterns because of newsletters

When you do find yourself blocked, you may see some error messages such as:

550 SC-004 Mail rejected by Outlook.com for policy reasons. A block has been placed against your IP address because we have received complaints concerning mail coming from that IP address. We recommend enrolling in our Junk Email Reporting Program (JMRP), a free program intended to help senders remove unwanted recipients from their email list. If you are not an email/network admin please contact your Email/Internet Service Provider for help.

550 5.7.1 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 (S3150). You can also refer your provider to http://mail.live.com/mail/troubleshooting.aspx#errors. [HE1EUR04FT063.eop-eur04.prod.protection.outlook.com]

The removal process for this is quite simple, you simple need to follow the steps listed below:

1. Review Server Logs and or Scripts to identify any possible malicious content such as spam being sent out via a compromised script or a compromised account. If the reason for the spam is not removed before submitting a blacklist removal request, you will be blacklisted again and for a longer period.
   • Possible log locations such as /var/log/exim_mainlog (cPanel) or /var/log/exim/mainlog (DirectAdmin)
   • Check for sendmail (php) lines from your websites.
2. Submit a request to Hotmail by following this link https://support.microsoft.com/en-us/supportrequestform/8ad563e3-288e-2a61-8122-3ba03d6b8d75, provide the following information:
   • Your name
   • Domain you're sending to: (live.com, hotmail.com, outlook.com or msn.com)
   • Contact Email
   • Timezone
   • Domain you're sending from: (i.e domain.com)
   • The type of company you are
   • IP Address of your Server
   • Type of server (is it dedicated or shared)
   • The error you received
   • URL of your website
3. Wait for a response from hotmail. Most responses take anywhere from 30mins to several hours. Once you receive a response hotmail will outline the action which has been taken and in most cases your blacklist will have been lifted.

If your blacklist has not been removed you will need to resolve anything they have identified or reply back to them asking why it cannot be lifted and they will provide you with a reason.