How to troubleshoot Office 365 SCL varying issues when deliverability is fine elsewhere?

Key findings

• Microsoft's unique filtering: SCL scores for Office 365 can vary significantly, even for emails sent from the same IP address with identical content, despite good performance on other email services.
• Limited direct support: Microsoft generally does not offer individual support for delivery issues outside their official ticketing system, which has been noted to be inconsistent for B2B (Office 365) issues.
• Engagement as a factor: Despite high open rates and users manually moving emails from spam, high SCL scores can persist, indicating that user engagement alone may not fully mitigate Microsoft's filtering.
• Content and reputation: The issue often stems from Microsoft's content analysis or perceived sender reputation, which operates differently from other email providers, highlighting the importance of understanding what SCL and BCL ratings mean.

Key considerations

• Recipient education: Actively advise recipients, especially those on Office 365, to check their spam folders and mark legitimate emails as 'Not Spam'. This can be done via banners on transactional websites or within the email itself.
• Persistence with support: Despite challenges, continue attempting to submit tickets through Microsoft's official sender support forms. While a 'wobbly' system, it remains the primary formal channel for resolution. Check Spotler's guide to Microsoft Outlook junk mail for more insights.
• Monitor authentication: Regularly verify your SPF, DKIM, and DMARC records are correctly configured and aligned, as these are fundamental for Microsoft's reputation assessment. For more, see our guide on troubleshooting Office 365 DKIM and SPF failures.
• Content optimization: While transactional emails are less prone to content-based filtering, consider subtle adjustments to subject lines or body text if specific patterns seem to trigger high SCL scores. Learn how to fix Outlook junk mail placement.

Key opinions

• Unpredictable SCLs: Many marketers report SCL scores varying wildly, even for identical emails, making it difficult to pinpoint specific issues.
• Transactional email challenges: Even with high open rates for transactional emails, Office 365 can still be the sole destination experiencing deliverability issues.
• Recipient action is key: Encouraging recipients to move emails out of spam folders is seen as a crucial way to signal positive engagement to Microsoft.
• Content manipulation attempts: Some marketers try altering content to see if it affects SCL, though results are often inconsistent (e.g., still landing in spam or quarantine).

Key considerations

• Prompt recipients to interact: Implement prompts on your website or app at the point of transaction, explicitly asking Office 365 users to check spam and mark emails as 'Not Spam'.
• Monitor google postmaster tools: While Microsoft doesn't directly care about Google's metrics, a low complaint rate on Google Postmaster Tools confirms good sender behavior generally, helping rule out broader issues. Read our ultimate guide to Google Postmaster Tools V2.
• Leverage engagement data: Use data like high unique open rates as evidence that emails are expected and wanted by recipients, strengthening your case when troubleshooting with Microsoft support.
• Understand Microsoft's specific challenges: Be aware that Microsoft email deliverability can be uniquely challenging, and that issues may persist despite efforts.

Key opinions

• Microsoft's policy: Microsoft generally does not allow its personnel to participate in public forums for deliverability questions, requiring all interactions to go through official ticketing systems.
• Distrust in ML: Some experts express skepticism about the consistency and transparency of Microsoft's machine learning engines for SCL scoring, sometimes humorously likening it to a random process.
• Limited recourse: Beyond filing forms and hoping for a response, there's often little immediate action experts can recommend due to Microsoft's rigid support structure.
• Consolidated forms: Microsoft has recently condensed its sender support forms to cover both Office 365 and consumer domains, aiming to streamline the process, though usability can still be an issue.

Key considerations

• Perseverance with tickets: Despite challenges with the ticketing system, it's the only official channel for Microsoft support, emphasizing the need for persistent submission even for unclear issues.
• Recipient engagement strategy: Implementing a strategy that guides recipients to proactively move emails from spam to inbox is crucial for improving sender reputation signals to Microsoft. This is covered in more detail in our article, how to troubleshoot Outlook email deliverability.
• Understand Microsoft's blackbox: Accept that Microsoft's filtering can be a less consistent experience compared to other ISPs, and focus on optimizing elements within your control. For example, ensuring you are not on a blocklist.
• No special treatment: Due to legal policy, Microsoft will not offer individual help or special treatment for delivery problems outside of their logged ticketing system.

Key findings

• SCL definition: SCL (Spam Confidence Level) is a numerical value assigned to incoming emails by EOP to indicate the likelihood of them being spam, ranging from 0 (safest) to 9 (highest confidence spam).
• SCL actions: Specific SCL values trigger predefined actions; for instance, SCL 5 typically marks an email as spam, while SCL 9 often results in quarantine, preventing delivery to the inbox.
• Factors influencing SCL: EOP uses a combination of factors, including sender reputation, content analysis, and advanced threat detection, to calculate the SCL for each message.
• Sender portals: Microsoft provides sender support portals (e.g., sender.office.com) for senders to check IP status and submit delisting requests, although these primarily address outright blocks rather than varying SCLs.

Key considerations

• Review official SCL guidance: Consult Microsoft's official documentation on SCL values and anti-spam policies to understand the expected behavior and thresholds.
• Confirm authentication: Ensure your SPF, DKIM, and DMARC records are correctly implemented and aligned according to standards to positively influence your sender reputation with Office 365. Further guidance on DMARC, SPF, and DKIM is available.
• Utilize sender support forms: Even if the issue isn't a hard block, submit detailed requests through Microsoft's dedicated sender support forms to document the problem and seek potential solutions.
• Content best practices: While not always explicitly detailed, adhering to general email content best practices, avoiding spammy triggers, and maintaining clean lists contribute to a better perceived sender score, as outlined in Microsoft's new sender requirements.