Summary
Despite a good IP reputation, emails may land in Outlook/Hotmail junk folders due to domain reputation, problematic content, user interactions, and feedback loops. Monitor Microsoft's Smart Network Data Services (SNDS), ensure proper authentication (SPF, DKIM, DMARC), and send engaging content. Good list hygiene is crucial. Check for blocklisting and address issues promptly. If delivered to the bulk folder, recipients moving the email to the inbox helps. Warm up IPs focusing on engaged users. Test content and monitor if emails initially land in the inbox before moving to junk.
Key findings
- Holistic Reputation: Deliverability depends not only on IP but also on domain reputation, content, user engagement, and feedback loops.
- SNDS Importance: Microsoft SNDS provides specific reputation data, crucial for Outlook/Hotmail deliverability.
- Authentication Matters: Proper authentication is essential to prove sender legitimacy.
- Engagement Signals: High engagement rates signal positive reputation, while low engagement can harm it.
- List Hygiene Critical: Clean email lists improve sender reputation and reduce junk folder placement.
- Content Triggers: Spammy content (words, formatting) triggers junk filters.
- Blocklist Impact: Listing on blocklists hurts deliverability, even with a good IP reputation.
- User Action Effects: Users moving emails from junk to inbox improves future delivery.
Key considerations
- Monitor SNDS: Regularly monitor SNDS to identify and address deliverability issues promptly.
- Authenticate Email: Implement SPF, DKIM, and DMARC to authenticate your sending domain.
- Engage Users: Focus on sending relevant and engaging content to improve open/click rates.
- Clean Lists: Regularly remove invalid and inactive email addresses from your list.
- Test Content: A/B test different subject lines and body content to avoid spam triggers.
- Manage Reputation: Address blocklist listings and improve overall sender reputation through best practices.
- Warm Up IP: Focus IP warmup on engaged users.
- Delivery Location: Monitor if emails go straight to Junk or Inbox initially.
What email marketers say
11 marketer opinions
Despite a good IP reputation, emails may still land in Outlook/Hotmail junk folders due to various factors. These include how users interact with your emails (marking them as junk), content-related issues (spam trigger words, excessive formatting), domain reputation problems, feedback loops where negative feedback trains Outlook's filters, lack of proper authentication (SPF, DKIM, DMARC), poor list hygiene (sending to invalid addresses), and low user engagement (low open/click rates). Microsoft also considers whether emails initially land in the inbox and then move to junk. Monitoring SNDS data and addressing identified issues, warming up IP addresses correctly, and opening support tickets with Microsoft when necessary are all recommended.
Key opinions
- User Interaction: Users marking emails as junk train Outlook's filters, affecting future deliverability.
- Content Matters: Spam trigger words, excessive formatting (all caps, exclamation points), and subject line issues can trigger spam filters.
- Domain Reputation: A negative domain reputation can override a good IP reputation and impact deliverability.
- Feedback Loops: Negative feedback from recipients (marking as junk) contributes to filtering decisions.
- Authentication: Proper authentication (SPF, DKIM, DMARC) is crucial for improving deliverability to Hotmail/Outlook.
- List Hygiene: Sending to invalid or inactive email addresses harms sender reputation and deliverability.
- User Engagement: Low open/click rates signal to Microsoft that your emails may not be valuable, impacting deliverability.
- Monitoring: Continuous monitoring of your sender reputation via SNDS helps identify and resolve deliverability issues.
- Delivery Path: It's important to know if the emails are landing in the inbox first before moving to junk. This indicates different issues than direct delivery to junk.
Key considerations
- Email Warmup: Focus on recipients who actively engage with your emails when warming up a new IP address.
- Content A/B Testing: A/B test different subject lines and body content to identify potential spam triggers.
- Microsoft SNDS: Regularly check and analyze data from Microsoft's Smart Network Data Services (SNDS) to proactively manage your IP and domain reputation.
- Relevance and Value: Focus on creating highly relevant and valuable content to improve user engagement and sender reputation.
- Remediation Plan: Establish a plan to address deliverability issues promptly, including opening a support ticket with Microsoft if necessary.
- Email List Cleaning: Purge any old, unengaged or invalid email addresses from your email list.
Marketer view
Email marketer from EmailGeek shares that users mark messages as junk which trains Outlook to do so. Senders need to use feedback loops, authenticate email, get added to address books, test content with Outlook, use a dedicated IP address, monitor sender reputation and follow best practices.
18 Jul 2022 - EmailGeek
Marketer view
Email marketer from Mailtrap Blog shares that a common reason for emails landing in the junk folder is the content itself. Using excessive exclamation points, all caps, or spam trigger words can negatively impact deliverability. Optimize your content for better results.
8 Jun 2023 - Mailtrap Blog
What the experts say
4 expert opinions
Even with a good IP reputation, emails can still end up in Outlook/Hotmail's junk folder. If messages are delivered to the bulk folder, recipients need to move them to the inbox. Warming up a new IP should focus on users who have already engaged. Maintaining a good sender reputation requires adhering to Microsoft's guidelines, monitoring SNDS data, and addressing issues promptly. Check your IP and domain against blocklists, as being listed can impact deliverability, even with a good IP reputation.
Key opinions
- User Action Required: If emails land in the bulk/junk folder, recipients moving them to the inbox helps improve future deliverability.
- Targeted Warmup: During IP warmup, focus on recipients who have previously opened or clicked your emails.
- SNDS Monitoring: Regular monitoring of Microsoft's Smart Network Data Services (SNDS) is essential for maintaining sender reputation.
- Blocklist Impact: Being listed on blocklists can negatively impact deliverability to Outlook/Hotmail, even with a good IP reputation.
Key considerations
- Recipient Education: Encourage recipients to move emails from the junk folder to their inbox if they want to receive future communications.
- Engagement Focus: Prioritize engaging with recipients who are most likely to interact positively with your emails.
- Proactive Reputation Management: Actively monitor and address any issues identified through SNDS to maintain a positive sender reputation.
- Blocklist Checks: Regularly check your IP and domain against common blocklists and take steps to be removed if listed.
Expert view
Expert from Word to the Wise, Laura Atkins, explains that to maintain a good sender reputation with Microsoft, ensure your sending practices are in line with their guidelines, monitor your SNDS data, and actively address any issues identified to avoid being flagged as spam.
14 Mar 2025 - Word to the Wise
Expert view
Expert from Email Geeks shares another solution to warm up a new IP is to focus on the people who have opened and clicked on the new IP and restart the warmup.
30 Oct 2021 - Email Geeks
What the documentation says
5 technical articles
Even with a good IP reputation, emails can still land in the junk folder due to various factors including negative domain reputation, problematic content, and user interactions. It's crucial to monitor Microsoft's Smart Network Data Services (SNDS) to understand how Microsoft views your IP reputation. Authentication, consistent IP usage, low complaint rates, and avoiding blocklists are vital. Also, pay attention to feedback loops from ISPs to identify problematic users or content that triggers spam reports.
Key findings
- Multiple Factors Affect Deliverability: Even with a good IP reputation, domain reputation, content, and user interactions play a significant role in email deliverability.
- Importance of SNDS: Microsoft's Smart Network Data Services (SNDS) provides specific insights into your reputation with Microsoft, which may differ from other services.
- Authentication is Key: Proper email authentication is crucial for preventing emails from being marked as spam.
- Consistent Sending Practices: Using a consistent IP address and maintaining low complaint rates improves deliverability.
- Feedback Loops: ISPs providing you with feedback data allows you to identify problematic sending patterns.
Key considerations
- Domain Reputation Management: Actively manage and monitor your domain reputation alongside your IP reputation.
- Content Optimization: Review and optimize email content to avoid triggering spam filters.
- Regular SNDS Review: Implement a process for regularly monitoring SNDS data to proactively address potential issues.
- Proactive Blocklist Monitoring: Ensure you domain and IP is not on any blocklists and monitor this regulary.
- Feedback Loop Processes: Implement processes for using feedback loops to identify and address problematic users or content.
Technical article
Documentation from Microsoft Learn explains that several factors can cause emails to land in the Junk Email folder, including the sender's IP address reputation, domain reputation, content of the message, and user interactions. Even with a good IP reputation, negative domain reputation or problematic content can trigger the junk filter.
8 Dec 2023 - Microsoft Learn
Technical article
Documentation from SparkPost explains that Microsoft's Smart Network Data Services (SNDS) provides data about your IP address reputation with Microsoft. Monitoring this helps identify if Microsoft is throttling your mail or marking it as spam, even if other services show a good reputation.
27 Jun 2024 - SparkPost
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