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

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

Bad email practices typically lead to serious deliverability problems like spam placements, blocked and dropped messages which have a direct negative impact on your sender reputation and email performance.

To protect their users from unsolicited emails, mailbox providers often put bad senders to the blacklist and do not deliver their messages to the target recipients. Gmail, Outlook/Hotmail, Yahoo, GoDaddy and some other major mailbox providers maintain their own blacklists to stop spammers.

If one day the open rate for your messages sent to Outlook/Hotmail emails became unusually low, then it's time to investigate the problem and find out whether or not you are blacklisted by Microsoft.

Why Hotmail Can Blacklist Your IP

Before you proceed with the blacklist removal, you must understand why you were listed and fix the problem. Once you stop the behavior that triggered the blacklist addition, Hotmail will usually remove your IP address automatically.

If you send multiple removal requests without fixing the problem, your case is submitted for additional screening. So, fix the problem first.

The most common reasons Hotmail blacklists an IP are:

– High volume of spam looking emails coming from an IP address.
– High bounce rates.
– Spam reports from Hotmail/Outlook users.
– Forward of a high level of spam to Hotmail/Outlook users.
– Misconfigured DNS Settings.
– Bad IP/domain reputation.

Your Hotmail/Outlook Blacklist Investigation Process

You can follow the steps below to identify if your email practices could lead to the IP blacklisting:

Review server logs or stats to see if there has been a spike in email volume.

Check your IP with your favorite blacklist lookup tool, for example, GlockApps IP Reputation Monitor.

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

Check your sending reputation at SenderScore.org.

Check for users bulk forwarding email to Hotmail.com and related domains.

Verify that email authentication related entries (PTR, DKIM, SPF) are correctly set up for your sending domain.

Check your Brightmail IP reputation and request the block removal if you are listed. Hotmail/Outlook uses the Brightmail anti-spam content filter. The Brightmail technology learns what email is 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 or bulked.

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.

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

Analyze your bounces for "mail blocks" coming from Hotmail/Outlook. You can use the GlockApps Bounce Monitor to track bounces and look for rejected emails from Hotmail.

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

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 notice has important information and gives you a clue about why your IP is blacklisted.

At first, you may see a 421 code when Hotmail starts throttling emails 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 CodeDescription
421 RP-001The 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-002The 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-003The 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-001Mail 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-002Mail 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-003Mail 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-004Mail 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-001Mail 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-002Mail 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-001Mail 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-002Mail 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 Hotmail/Outlook's Blacklist

Before contacting Microsoft:

– Investigate and fix the issue that had triggered the IP blacklisting.

– Check that your IP is no longer listed in Spamhaus or other major public email blacklists.

– Check that your SenderScore is over 75, preferably 80.

– Check that your DNS settings are correct.

Now you can start the removal process.

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

If you provide reliable information and are truly not spamming their users, you will typically see your IP removed from the blacklist in 2-3 business days.

Also, visit the troubleshooting and junk email pages at Microsoft. They highlight other things that could impact your deliverability if the above steps do not help.

Read also:
How to Remove Your IP Address from Gmail’s Blacklist
How to Remove Your IP Address from the Yahoo!’s Blacklist

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