Summary
Troubleshooting email deliverability issues with Microsoft Exchange Online Protection requires a comprehensive approach encompassing technical configuration, content optimization, and reputation management. Key steps include: properly authenticating email with SPF, DKIM, and DMARC; monitoring and maintaining a positive IP and sender reputation (using tools like SenderBase); analyzing anti-spam message headers and SCL thresholds; using spam testing tools; ensuring clean and engaged email lists; carefully reviewing email content for spam triggers and bad URLs; implementing DMARC policies and setting up feedback loops; personalizing email content; and actively managing SCL thresholds within Exchange Online Protection. Understanding spam filter feedback and adapting practices accordingly is crucial for sustained deliverability.
Key findings
- Email Authentication: SPF, DKIM, and DMARC authentication are vital for verifying sender identity and improving deliverability.
- Sender Reputation Monitoring: Monitoring IP and domain reputation through services like SenderBase is crucial to identify and address deliverability issues.
- Content Analysis and Optimization: Avoiding spam trigger words, ensuring URLs are reputable, and personalizing content can significantly improve inbox placement.
- List Hygiene: Maintaining a clean and engaged email list is essential for sender reputation and deliverability.
- Spam Filter Feedback: Analyzing feedback from spam filters and adjusting practices accordingly helps refine email campaigns and improve deliverability.
Key considerations
- Technical Configuration: Properly configure SCL thresholds within Exchange Online Protection to balance spam filtering with the risk of false positives.
- Reputation Management: Actively monitor blacklists and adjust sending volumes to maintain a positive sender reputation.
- Content Testing: Utilize spam testing tools to preview how emails will be treated by various filters before sending.
- Engagement Metrics: Segment email lists to focus on engaged recipients, as Exchange Online Protection considers engagement metrics when determining deliverability.
- Adaptive Strategies: Regularly adapt email practices based on spam filter feedback and evolving best practices to maintain consistent deliverability.
What email marketers say
10 marketer opinions
Troubleshooting email deliverability issues with Microsoft Exchange Online Protection involves a multi-faceted approach. Key steps include authenticating your email using SPF, DKIM, and DMARC; monitoring and maintaining a positive IP address reputation; using spam testing tools; ensuring clean and engaged email lists; carefully reviewing email content to avoid spam triggers and bad URLs; implementing DMARC policies; setting up feedback loops; and personalizing email content. Effectively addressing these areas can significantly improve inbox placement and reduce the likelihood of emails being flagged as spam.
Key opinions
- Authentication: Authenticating emails with SPF, DKIM, and DMARC is crucial to prove authorization and improve deliverability.
- IP Reputation: Monitoring and maintaining a positive IP address reputation is essential as Exchange Online Protection filters based on sender reputation.
- Content: Carefully reviewing email content for spam triggers and avoiding URLs with poor reputation is important for inbox placement.
- List Hygiene: Regularly cleaning email lists to remove unengaged recipients enhances sender reputation and deliverability.
- Testing: Using spam testing tools before sending can identify and resolve content or configuration issues.
Key considerations
- DMARC Policy: Implementing and enforcing a DMARC policy helps prevent domain spoofing and instructs receiving servers on handling authentication failures.
- Feedback Loops: Setting up feedback loops allows you to receive notifications when recipients mark your emails as spam, enabling prompt issue resolution.
- Personalization: Personalizing and customizing email content can improve engagement and prevent generic messages from being flagged as spam.
- Content Testing Tools: Content testing tools should be used before sending to identify the cause of deliverability issues with Exchange Online Protection.
- Content Testing Tools: Review content and ensure that URLs within the email body do not point to domains with poor reputation scores, as these can be flagged by Microsoft Exchange Online Protection.
Marketer view
Email marketer from Sendinblue advises monitoring your IP address reputation as Microsoft Exchange Online Protection often filters emails based on the sender's IP reputation. They suggest using tools to check if your IP is blacklisted.
1 Jun 2025 - Sendinblue
Marketer view
Email marketer from Litmus suggests setting up and enforcing a DMARC policy to instruct receiving mail servers (including Microsoft Exchange Online Protection) on how to handle emails that fail authentication checks. This can help prevent domain spoofing and improve deliverability.
8 Apr 2025 - Litmus
What the experts say
6 expert opinions
Troubleshooting email deliverability with Microsoft Exchange Online Protection involves several key steps. Experts recommend checking URLs for poor reputations, ensuring secure (HTTPS) links, reasonable message sizes, and clean landing pages. Proper email authentication (SPF, DKIM, DMARC) and active management of sender reputation, including blacklist monitoring, are essential. Additionally, understanding spam filter feedback, segmenting email lists to focus on engaged recipients, and optimizing content by avoiding spam triggers improve deliverability.
Key opinions
- URL Reputation: Check all URLs within the email for poor reputations that could trigger spam filters.
- Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) is in place and correctly configured.
- Sender Reputation: Actively manage your sender reputation, including monitoring blacklists and maintaining consistent sending volumes.
- Engagement: Focus on sending emails to highly engaged recipients to improve inbox placement.
- Content Optimization: Optimize email content by avoiding spam triggers such as excessive capitalization and spammy keywords.
Key considerations
- Feedback Analysis: Carefully analyze the feedback provided by spam filters to identify and rectify specific issues.
- Link Security: Ensuring the use of HTTPS links for any URL included in the email.
- Segmented Lists: Segment your email lists so only active users are receiving the email and new sign ups and removed.
Expert view
Expert from Email Geeks suggests starting with checking the URLs in the messages to see if they are linking to or mentioning a domain with a poor reputation. Otherwise, they recommend swapping out text to identify what might be causing the issue.
31 Mar 2023 - Email Geeks
Expert view
Expert from Spam Resource explains that understanding the specific feedback provided by spam filters within Microsoft Exchange Online Protection is crucial. Reviewing detailed reports can identify particular phrases, links, or code snippets that trigger spam filters.
11 May 2025 - Spam Resource
What the documentation says
5 technical articles
Troubleshooting email deliverability issues with Microsoft Exchange Online Protection involves configuring SCL thresholds, analyzing anti-spam message headers, properly setting up DKIM, verifying SPF records, and monitoring sender reputation on SenderBase. Adjusting SCL thresholds allows customization of spam filtering aggressiveness. Analyzing message headers, especially the X-MS-Exchange-Organization-SCL value, provides insights into triggered filters. Correct DKIM and SPF setup ensures authorized email sending, preventing fraudulent flags. Monitoring SenderBase helps identify and address sender reputation problems.
Key findings
- SCL Configuration: Configuring SCL thresholds allows customization of spam filtering aggressiveness within Exchange Online Protection.
- Header Analysis: Analyzing anti-spam message headers, particularly the X-MS-Exchange-Organization-SCL value, provides insights into triggered filters.
- DKIM Setup: Properly setting up DKIM is crucial for ensuring outbound emails are not marked as spam.
- SPF Verification: Verifying SPF records ensures that authorized sending servers are correctly identified, preventing fraudulent flags.
- Sender Reputation: Monitoring sender reputation on SenderBase helps identify and address deliverability issues related to poor reputation.
Key considerations
- Threshold Adjustment: Carefully adjust SCL thresholds to balance spam filtering effectiveness with the risk of false positives.
- Regular Monitoring: Regularly monitor sender reputation on SenderBase and take corrective actions to maintain a positive reputation.
- Authentication Standards: Adhere to and regularly update email authentication standards (SPF, DKIM) to prevent deliverability problems.
Technical article
Documentation from Microsoft Learn explains that you can configure SCL (Spam Confidence Level) thresholds in Exchange Online Protection to define what happens to messages based on their spam score. These settings can be adjusted to manage how aggressively messages are filtered.
10 Sep 2021 - Microsoft Learn
Technical article
Documentation from Microsoft Learn explains the importance of setting up DKIM (DomainKeys Identified Mail) correctly. This is important to ensure that outbound email isn't marked as spam. The documentation details the exact steps for configuring DKIM.
24 Aug 2024 - Microsoft Learn
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