How to Remove Your IP Address from the Hotmail/Outlook Blacklist

Check if your domain is blacklisted by Microsoft (FREE)

Your sender reputation and email performance are directly dependent on your sending workflow. If you have bad sending practices, it can lead to serious deliverability problems and ultimately land you in the spam folder. Likewise, safe senders with proper email authentication, positive reputation, and great list management, should have better deliverability and inbox placement.

In order to protect their users from unsolicited emails, mailbox providers developed blacklists to flag bad senders, somewhat like a blocked senders list.

Mailbox providers reference blacklists to identify bad senders and decide where to place their emails: in the spam folder, or block them completely.

Gmail, Outlook/Hotmail, Yahoo, GoDaddy, and some other major mailbox providers maintain their own blacklists to stop spammers from messaging their users.

If your email’s open rate suddenly drops for your Outlook or Hotmail contacts, then it’s time to investigate and find out if Microsoft blacklisted your domain.

This post will show you:

• If you’ve been blocked by Microsoft
• Why Microsoft may block your message
• How to find and fix the reason why Microsoft blocked your IP
• How to Remove your domains from the Outlook/ Hotmail Blacklist

Why Hotmail Can Blacklist Your IP

Before you request to be removed from the Outlook blacklist, you need to identify why you were blacklisted in the first place. Once you stop the behavior that caused you to be blocked, in most cases, Hotmail will remove your IP address from the block list.

Important Note: Don’t submit multiple removal requests without fixing the problem. Your case will just be submitted for additional screening. So, fix the problem first.

Common reasons Hotmail blacklists an IP:

• If your IP address is sending spam messages at a high volume
• If you get high bounce rates
• If you get spam reports from Hotmail or Outlook users
• If you forward a high level of spam mail to Hotmail or Outlook users
• If your DNS settings are misconfigured (SPF, DMARC, and DKIM records)
• If you have a bad IP/domain reputation

How to determine if you are on the Hotmail/Outlook Blacklist

Follow the steps below to troubleshoot why you may be on Microsoft’s list of blocked senders:

1. Review server logs or stats to see if there has been a spike in email volume or use our DMARC Analytics tool to monitor your email traffic.
2. Check your sending score with our Inbox Email Tester..
3. Check for users bulk forwarding email to Hotmail.com and related domains. Use our DMARC Analyzer to see who is sending emails from your domain.
4. Verify that the email authentication-related entries (PTR, DKIM, SPF) are correctly set up for your sending domain by running a free spam test.
5. Check your Symantec IP reputation and request removal if you are listed. Hotmail and Outlook use the Symantec anti-spam content filter. Symantec technology learns what type of emails are considered spam from all mail received in their spam trap network. If a high volume of your mail is considered suspicious, your IP address could be blocked.
6. Sign up for Microsoft’s Smart Network Data Services (SNDS) and see the traffic originating from your IP address such as the volume of sent emails and complaint rates. The data is collected from the log files of the inbound Hotmail servers and other servers at Hotmail and Microsoft.
7. Analyze your bounces for “mail blocks” coming from Hotmail or Outlook.

Example of a 550 Hotmail bounce code:

host mx4.hotmail.com[65.55.37.72] said: 550 SC-001 Mail rejected by Windows Live Hotmail 
 
for policy reasons. Reasons for rejection may be related to content with spam-like characteristics
 
or IP/domain reputation problems. If you are not an email/network admin please contact your
 
E-mail/Internet Service Provider for help. Email/network admins, please visit MSN Postmaster
 
for email delivery information and support (in reply to MAIL FROM command)

The Hotmail rejection notices have important information and give you a clue about why your IP is blacklisted.

At first, you may see a 421 code when Hotmail starts throttling messages from your IP. If Hotmail users report your emails as spam, you will quickly get a 550 block on your server’s IP address.

Complete list of Hotmail/Outlook SMTP bounce codes:

SMTP Error Code	Description
421 RP-001	The mail server IP connecting to Outlook.com server has exceeded the rate limit allowed. Reason for rate limitation is related to IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
421 RP-002	The mail server IP connecting to Outlook.com server has exceeded the rate limit allowed on this connection. Reason for rate limitation is related to IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
421 RP-003	The mail server IP connecting to Outlook.com server has exceeded the connection limit allowed. Reason for limitation is related to IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
550 SC-001	Mail rejected by Outlook.com for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
550 SC-002	Mail rejected by Outlook.com for policy reasons. The mail server IP connecting to Outlook.com has exhibited namespace mining behavior. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
550 SC-003	Mail rejected by Outlook.com for policy reasons. Your IP address appears to be an open proxy/relay. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
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 DY-001	Mail rejected by Outlook.com for policy reasons. We generally do not accept email from dynamic IP’s as they are not typically used to deliver unauthenticated SMTP email to an Internet mail server. If you are not an email/network admin please contact your Email/Internet Service Provider for help. http://www.spamhaus.org maintains lists of dynamic and residential IP addresses.
550 DY-002	Mail rejected by Outlook.com for policy reasons. The likely cause is a compromised or virus-infected server/personal computer. If you are not an email/network admin please contact your Email/Internet Service Provider for help.
550 OU-001	Mail rejected by Outlook.com for policy reasons. If you are not an email/network admin please contact your Email/Internet Service Provider for help. For more information about this block and to request removal please go to: http://www.spamhaus.org.
550 OU-002	Mail rejected by Outlook.com for policy reasons. Reasons for rejection may be related to content with spam-like characteristics or IP/domain reputation. If you are not an email/network admin please contact your Email/Internet Service Provider for help.

How to Request Removal from the Hotmail/Outlook Blacklist

Before contacting Microsoft to remove your IP from the Hotmail/ Outlook blacklist, use Inbox Insight to:

1. Investigate and fix the issue that triggered the IP blacklisting.
2. Check that your IP is no longer listed in Spamhaus or other major public email blacklists.
3. Check that your sender score is over 75, preferably 80 or more.
4. Check that your DNS settings are correct.

Now you can start the Outlook/ Hotmail blacklist removal process.

Complete the Microsoft Sender Information Form and provide all of the information requested.

If you provide reliable information and are truly not sending spam, you will typically see your IP removed from their blocked senders list in 2-3 business days.

If the steps listed above do not help remove your message from the junk email folder, visit the Microsoft troubleshooting support and junk email pages. They highlight other things that could impact your messages’ deliverability to a Microsoft email account.

Also, read the Improving E-mail Deliverability into Windows Live Hotmail PDF guide from Microsoft where they cover their best email sending practices and 3 deliverability scenarios that will help you understand why Outlook and Hotmail may send your message to Spam or block it completely.

Additional Resources:

IP Blacklist Removal – How To Fix a Blacklisted IP Address

How to Remove Your IP Address from Gmail’s Blacklist

How to Remove Your IP Address from the Yahoo!’s Blacklist