Why are my emails going to the spam folder or "Other" tab in Hotmail/Outlook?

Microsoft's filters are particularly stringent. Common reasons include poor sender reputation (due to high bounce rates or spam complaints), lack of proper email authentication ( SPF, DKIM, DMARC ), low engagement from recipients, and content that triggers spam filters. Sometimes, emails are just filtered to the Other tab rather than being junked.

What are the best ways to improve deliverability to Microsoft email addresses?

You should focus on improving your sender reputation, ensuring all email authentication records are correctly configured, and maintaining a clean, engaged email list. Regularly check your complaint rates and list hygiene. Encouraging subscribers to add you to their address book can also significantly help.

My open rates for Hotmail/Outlook are very low, even if emails aren't junked. Why?

Low open rates, especially at Microsoft domains , often indicate your emails are not reaching the primary inbox, or are simply not being noticed. This can be due to placement in the junk folder, the Other tab, or a general decline in sender reputation causing lower visibility. Focus on list quality and sending relevant content.

How often should I monitor my email deliverability to Hotmail/Outlook?

Regularly monitoring your metrics in Outlook's SNDS is crucial. Pay attention to complaint rates, junking rates, and reputation scores. If you consistently maintain good sending practices, it demonstrates to Microsoft that you are a trustworthy sender.

Why are emails experiencing low deliverability and open rates with Hotmail and Outlook? - Sender reputation - Email deliverability - Knowledge base

Many email marketers and businesses frequently encounter issues with low deliverability and poor open rates when sending to Hotmail and Outlook accounts. This can be incredibly frustrating, especially when your emails perform well with other mailbox providers. The challenges with Microsoft's email services often stem from their robust filtering mechanisms, which are designed to protect users from unwanted mail, including spam and phishing attempts.

I've seen many senders struggle to get their legitimate emails into the inbox, despite having strong engagement metrics elsewhere. This often leads to a significant drop in overall campaign performance and can impact crucial communications like transactional emails and newsletters. It's a common pain point that requires a targeted approach to resolve.

How Hotmail and Outlook filter emails

Microsoft (including Hotmail and Outlook) uses sophisticated algorithms to determine whether an incoming email should land in the inbox, the junk folder, or be rejected entirely. Their filtering system prioritizes user safety and experience, which means even legitimate senders can face issues if they don't meet specific criteria.

Key to their filtering is Sender Support in Outlook.com (SNDS) and the Junk Mail Reporting Program (JMRP). These tools provide senders with insights into their reputation, complaint rates, and deliverability data. Actively monitoring these programs helps you understand how Microsoft views your sending practices and if your IP address spam reputation is too low.

A crucial factor is your sender reputation. This isn't just about your domain, but also the IP address you use to send emails. A poor email domain reputation can lead to emails going directly to the spam folder. Factors like sending volume, bounce rates, and spam complaints all contribute to this score.

If you notice a sudden drop in deliverability to Microsoft accounts, it's possible your IP or domain has been placed on a blocklist (or blacklist). While some blocklists are public, many are internal to Microsoft, meaning you won't find your domain listed on common blocklist checking tools. This makes troubleshooting more complex.

Essential email authentication for Microsoft

One of the most fundamental steps to ensuring good deliverability to any mailbox provider, especially Hotmail and Outlook, is implementing strong email authentication. This includes SPF, DKIM, and DMARC.

These protocols verify that the emails claiming to be from your domain are legitimate and authorized. Without proper authentication, your emails are far more likely to be flagged as suspicious and sent to the junk folder. Microsoft (and other major mailbox providers like

Gmail and

Yahoo) have recently tightened their requirements, making these authentication measures non-negotiable for senders, especially those sending in bulk.

SPF, DKIM, DMARC basics

SPF (Sender Policy Framework) is a DNS TXT record that specifies which mail servers are authorized to send email on behalf of your domain. DKIM (DomainKeys Identified Mail) adds a digital signature to your emails, allowing recipients to verify that the email was not altered in transit. DMARC (Domain-based Message Authentication, Reporting, and Conformance) builds on SPF and DKIM, providing instructions to receiving mail servers on how to handle emails that fail authentication, and offering reporting capabilities.

For bulk senders, Microsoft (and Gmail and Yahoo) have introduced new rules for 2024. These requirements include mandating DMARC, an easy unsubscribe option, and maintaining a low spam complaint rate. Failing to meet these can severely impact your deliverability to their users.

Content, engagement, and recipient interaction

Even with perfect authentication, your email content and how recipients interact with your emails play a huge role in deliverability. Microsoft's filters pay close attention to user engagement. If recipients consistently ignore, delete, or mark your emails as spam, your sender reputation will suffer, leading to lower inbox placement.

Low open rates are a clear signal to ISPs that your subscribers aren't engaged. This is a common issue for many senders. If your email open rates are declining, particularly for Hotmail and Outlook accounts, it might be due to a combination of factors, including content quality and list hygiene.

Content pitfalls

Spammy keywords: Using excessive capitalization, exclamation marks, or words commonly associated with spam (e.g., "free," "win," "guarantee").
Image-heavy emails: Emails relying too heavily on images with little text can trigger spam filters, as they might be trying to hide malicious content. Ensure you use proper alt text.
Broken links or formatting: Poorly coded HTML or broken links can negatively impact trust and deliverability.

Engagement strategies

List hygiene: Regularly clean your email list to remove inactive or invalid addresses, reducing bounces and spam trap hits.
Segmentation: Send targeted content to engaged segments of your audience. This improves relevance and, consequently, engagement.
Ask for whitelisting: Encourage subscribers to add your email address to their address book, a strong signal of trust to Microsoft.

Another specific challenge with Outlook is the Focused Inbox feature, which separates emails into "Focused" and "Other" tabs. Many marketing emails, even legitimate ones, often land in the "Other" tab, leading to lower visibility and, consequently, lower open rates. This isn't always a spam issue, but rather a categorization challenge that requires consistent positive engagement signals to overcome.

Views from the trenches

Best practices

Actively monitor your sender reputation using Microsoft's SNDS and JMRP programs, and address any negative trends promptly.

Implement and maintain robust email authentication protocols, including SPF, DKIM, and DMARC, ensuring full compliance with recent requirements.

Routinely clean your email lists to remove inactive subscribers, hard bounces, and known spam traps to improve overall list health.

Segment your audience and send highly relevant, engaging content to increase opens, clicks, and positive interactions.

Encourage subscribers, especially Hotmail and Outlook users, to add your email address to their contacts or address book.

Common pitfalls

Ignoring low open rates for Hotmail/Outlook, assuming it's a general issue, without digging into specific causes.

Failing to implement DMARC with a policy stronger than 'p=none', missing out on critical authentication benefits.

Sending emails to unengaged or old segments of your list, which can lead to increased spam complaints and reduced reputation.

Using generic or spammy subject lines and content that trigger Microsoft's aggressive spam filters.

Not having a clear and easy unsubscribe mechanism, leading to higher spam complaint rates instead of opt-outs.

Expert tips

Focus on segmenting your most active subscribers. Microsoft heavily weights recent engagement.

If your open rates are low but delivery looks good, investigate the Focused/Other tab placement.

Consider contacting Microsoft support directly for persistent issues, but be prepared for a long process.

Avoid relying solely on images in your email content. Balance images with text and use alt tags.

Educate your customers on how to move your emails to their primary inbox and add you to their contacts.

Marketer view

Marketer from Email Geeks says Hotmail's filters have been very aggressive recently, causing issues for many senders.

2019-05-07 - Email Geeks

Marketer view

Marketer from Email Geeks says they've seen a constant decline in opens from Hotmail addresses, especially from web clients, and suspects the Focused/Other tab is a major cause rather than pure filtering.

2019-05-07 - Email Geeks

Improving your Hotmail and Outlook deliverability

Navigating deliverability challenges with Hotmail and Outlook can be complex, but it's not insurmountable. It requires a multi-faceted approach focusing on technical setup, sender reputation, and recipient engagement.

By understanding Microsoft's filtering priorities, implementing robust email authentication (SPF, DKIM, DMARC), and consistently sending relevant, engaging content to a clean and active list, you can significantly improve your deliverability to these crucial inboxes. Remember, consistent monitoring and adaptation are key to long-term success in email marketing.