Why are my emails not delivering to Microsoft inboxes?

Email marketer from Mailjet advises monitoring feedback loops (FBLs) provided by Microsoft to understand if recipients are marking emails as spam. They suggest promptly removing users who complain from email lists to prevent future deliverability problems.

Email marketer from Email Marketing Forum shares that Microsoft is sensitive to sudden spikes in email volume from new or unestablished senders. They suggest gradually increasing sending volume to build a positive sender reputation over time.

Email marketer from Campaign Monitor explains that DMARC policy of 'reject' for unauthenticated email can cause delivery failures with Microsoft if your emails fail SPF or DKIM checks. They recommend ensuring proper SPF and DKIM configuration and reviewing DMARC reports to identify and resolve authentication issues.

Email marketer from Reddit shares that using shared IP addresses can lead to deliverability problems with Microsoft due to the actions of other senders on the same IP. They recommend switching to a dedicated IP address to improve sender reputation.

Email Marketer from SendGrid answers highlights the need to warmup your IP address, slowly increasing your mailing volume and slowly introducing yourself to their systems so that you aren't identified as spam.

Email marketer from Neil Patel's blog shares that low engagement (opens and clicks) can negatively impact deliverability to Microsoft inboxes. He recommends cleaning email lists, segmenting audiences, and sending targeted content to improve engagement and sender reputation.

Email marketer from StackOverflow states that sending high volumes of email to Microsoft without proper infrastructure setup (reverse DNS records, valid HELO/EHLO) can result in delivery issues. They recommend ensuring all technical aspects of email sending are correctly configured.

Email marketer from EmailOnAcid recommends testing email content for spam triggers before sending to a large audience. They suggest using tools that analyze content for common spam keywords and identify potential formatting issues that could trigger spam filters.

Email marketer from GlockApps recommends using a deliverability testing tool to check inbox placement rates with different email providers, including Microsoft. This allows identifying potential issues with content, IP address, or domain reputation before sending to a large audience.

Expert from Email Geeks advises ensuring everything is technically correct, as even seemingly minor issues can impact delivery.

Expert from Spam Resource explains that Microsoft's filtering can be aggressive, and suggests checking your sending reputation and ensuring proper authentication (SPF, DKIM, DMARC). He also highlights that Microsoft sometimes blocks emails for seemingly arbitrary reasons, and engaging with their support can be necessary.

Expert from Email Geeks shares that while responses are often form letters, there are real people responding and mitigation is sometimes granted. They suggest replying back to argue your case or asking for escalation with clear reasons.

Expert from Email Geeks suggests reaching out to Microsoft to request mitigation for delivery issues.

Expert from Email Geeks explains that Microsoft has aggressive filters and outlines steps to address delivery issues: checking for IP address blocks (and reaching out to MS for mitigation), addressing mail going to spam (by backing off sending and gradually adding addresses with clear permission), and dealing with mail being thrown away (though there's no clear path).

Expert from Word to the Wise explains that Microsoft uses various factors to filter emails including content, reputation, and user engagement. She advises monitoring your sending reputation using tools like SNDS, ensuring your emails are properly authenticated, and actively managing your subscriber list to remove inactive users.

Expert from Email Geeks shares their experience of having to stop sending some automated emails to Microsoft domains and occasionally having to contact Microsoft to resolve blocks on their monthly email.

Expert from Email Geeks emphasizes that getting everything technically correct is crucial for achieving inbox delivery, although it doesn't guarantee it.

Expert from Email Geeks explains that Microsoft will either mitigate or provide a reason for not doing so, and sometimes requires pushing back with explanations.

Documentation from AuthSMTP explains that maintaining a good sender reputation is crucial for successful email delivery to Microsoft. They recommend consistently authenticating emails (SPF, DKIM, DMARC), avoiding spam traps, and actively managing email lists to remove inactive subscribers.

Documentation from RFC editor highlights that having a valid reverse DNS record (PTR record) that matches the sending IP address to the sending domain is an important part of creating trust in mail systems and that this improves deliverability.

Documentation from SparkPost explains that Microsoft uses a sophisticated spam filtering system (SmartScreen) that considers numerous factors, including sender reputation, content, user complaints, and authentication. It recommends monitoring SNDS data and the Junk Mail Reporting Program (JMRP) to identify issues and address them promptly.

Documentation from Microsoft Learn explains that email delivery issues can arise from various factors, including IP reputation, content filtering, authentication failures (SPF, DKIM, DMARC), and sender reputation. They advise checking the sender's IP address against blocklists, ensuring proper email authentication, and monitoring sender reputation through tools like SNDS and JMRP.

Documentation from Microsoft SNDS explains that SNDS program is designed for helping you understand your reputation on their services and make improvements to it to improve your general mail flow to Microsoft Services. Microsoft encourages mail administrators with questions or concerns to leverage this tool.