How to solve Microsoft deliverability issues?

Microsoft Deliverability

Solving Microsoft Deliverability Mysteries for Email Success! Are your emails disappearing into the digital abyss? Sometimes, it’s a challenge to make sure they reach people who use Microsoft email services like Hotmail,, Live, and MSN. These services are owned by Microsoft and are used by many people worldwide. If you run an online business, a significant number of your customers, around 15-20%, might be using Microsoft email.

When your emails don’t make it to these Microsoft mailboxes, it can impact how many people open and engage with your emails. And that, in turn, affects how many people visit your website or make purchases. So, it’s important to learn how to improve Microsoft Deliverability to its email services and keep your customers engaged.

Why Does Microsoft Block My Emails?

There can be several reasons why Microsoft might block your emails. Here are some common reasons:

1. Poor Sender Reputation: If your email sending practices have raised red flags in the past, such as sending a high volume of spam or receiving numerous complaints from recipients, Microsoft may block your emails to protect their users.

2. Spam Content: If the content of your emails triggers spam filters or contains suspicious elements like excessive use of promotional language, misleading subject lines, or known spam keywords. Microsoft may flag them as spam and block their delivery.

3. Authentication Issues: If your emails fail authentication checks, such as missing or incorrect SPF (Sender Policy Framework) or DKIM (DomainKeys Identified Mail) records. Microsoft’s filters may view them as suspicious and block their delivery.

4. IP Address Reputation: If your email server’s IP address is associated with spamming activities or has a poor reputation. Microsoft may block emails originating from that IP to protect their users.

5. User Complaints: If recipients mark your emails as spam or consistently move them to the junk folder, Microsoft’s system may learn from this feedback and start blocking your emails for future deliveries.

To avoid email blocking by Microsoft, it’s essential to follow best practices such as maintaining a good sender reputation, ensuring proper email authentication, crafting relevant and engaging content, and promptly addressing any user complaints.

Understanding Microsoft’s Email Filtering System

Microsoft’s spam filtering with Exchange Online Protection (EOP) relies on previously identified spam and phishing threats as well as collected user feedback from to detect junk email. The identified junk email is automatically classified and separated from legitimate inbound messages. The O365 spam filter prevents inboxes from getting filled up with useless emails and ensures smooth communication across and beyond an organization’s network.

How to Check the Microsoft Blacklist?

To check if your domain or IP address is blacklisted by Microsoft, you can follow these steps:

1. Visit the Microsoft Remote Connectivity Analyzer website (

2. Scroll down to the “Mailflow” section and click on the “Inbound SMTP Email” option.

3. Enter your email address in the “Email Address” field and click on the “Next” button.

4. On the next page, select the “Manual server settings” option and enter your email server details.

5. Click on the “Perform Test” button to initiate the test.

6. The tool will check your email server’s connectivity and perform various tests, including checking for blacklisting.

7. After the test is completed, you will see the results, which will indicate whether your domain or IP address is blacklisted by Microsoft or not.

Additionally, you can also use online blacklist checking tools that provide comprehensive checks across multiple blacklists, including Microsoft’s. These tools allow you to enter your domain or IP address and perform a scan to see if you are listed on any blacklists.

Guidelines for Seeking Removal from Microsoft’s Blacklist

To request removal from Microsoft’s blacklist, follow these steps:

1. Visit the Junk Mail Reporting Program (JMRP): Microsoft provides the JMRP, an online platform where you can submit a removal request. Access the JMRP portal and provide accurate information about your email sending practices and the actions you have taken to fix the problem.

2. Submit Removal Request: Fill out the required details in the removal request form, including your contact information, email server details, and a clear explanation of the steps you have taken to resolve the issue. Be thorough and concise in your explanation to ensure a better understanding of the situation.

3. Follow Up and Monitor: After submitting the removal request, closely monitor your email deliverability to Microsoft-owned mailboxes. Check for any improvement in the delivery rates and observe any feedback or communication from Microsoft regarding your request.

Remember that the removal process may take time, as Microsoft needs to review and assess the provided information. Be patient and proactive in addressing any concerns raised by Microsoft during the review process.

What is SNDS?

SNDS stands for Smart Network Data Services, which is a free service provided by Microsoft to email senders. It offers valuable insights and data related to email delivery and performance to domains hosted on Microsoft’s email platforms, including and Hotmail.

The SNDS Microsoft service provides senders with detailed information about their email sending practices and reputation. It offers metrics such as volume, complaint rates, and spam trap hits, allowing senders to monitor the health of their email campaigns and identify potential issues.

By accessing SNDS, email senders can gain visibility into their email deliverability to Microsoft domains. They can identify patterns, track changes in email performance, and take proactive measures to improve their sender reputation and deliverability.

SNDS is a valuable tool for email senders who want to maintain a good relationship with Microsoft and ensure their emails reach the intended recipients’ inboxes. It provides actionable data and insights to help senders optimize their email practices and maintain high deliverability rates.

Follow Microsoft’s Best Practices

The following is a summary of best practices for sending email to Microsoft users. Microsoft recommends following their best practice guidelines to help avoid deliverability issues.

1. Register IPs In SNDS/JMPR: To activate the service, you need to register the IPs in SNDS/JMRP. Once done, you can view detailed data like reputation, filtered status, complaint rate, spam trap information, etc., for each IP. 

2. Maintain List Hygiene: Make sure your mailing list is always clean and validated. Hitting high hard bounces (>0.5%) will damage your reputations at Microsoft.

3. Be Cautious of Spam Traps: If a sender is hitting too many spam trap addresses, their IPs will  likely be blocklisted by SpamHaus, Spamcop, and other similar platforms. Microsoft considers such blocklisted senders as spammers and blocks all emails from them. 

4. Be Consistent With Email Send Volume And Frequency: Being inconsistent will harm your reputation at Microsoft. So always maintain consistency in email send volume and frequency. 

5. Warming Up A New IP/Domain: Start with very low volumes and gradually increase as per the acceptance. Also, make sure that all the authentications (SPF/DKIM/DMARC) are in place and passing.


In summary, it’s really important for businesses and email marketers to fix problems with sending emails to Microsoft platforms like and Hotmail. By learning about what affects email delivery and using smart tactics, we can make sure our emails reach more people successfully.

By following these tactics and keeping an eye on how Microsoft’s email filters work, we can improve our chances of delivering emails to Microsoft users. This means more people will see our messages, and our email marketing will be more successful overall.

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