Why is SNDS down and are Outlook inboxing rates affected?

9 Marketer opinions 3 Expert opinions 4 Technical articles 3 Resources

Summary

SNDS outages are a recurring issue, frequently linked to Microsoft maintenance, updates, or technical problems. These outages can cause temporary data unavailability or delays. While some users observe a correlation between SNDS downtime and fluctuations in Outlook inboxing, it's generally understood that SNDS data is an indicator, not a direct cause of inboxing problems. Inbox placement is influenced by a complex interplay of factors including sender reputation, email authentication (SPF, DKIM, DMARC), content quality, user engagement, spam complaints, and traffic volume. Industry experts recommend monitoring Microsoft support channels during outages, checking with peers to verify widespread issues, proactively monitoring deliverability metrics beyond SNDS, and ensuring proper email authentication implementation.

Key findings

Recurring Outages: SNDS experiences periodic outages, often due to maintenance, updates, or technical issues at Microsoft.
Data Delays: Delays in SNDS data reporting can occur due to processing times and system load.
Limited Causal Link: While a correlation may exist, SNDS data isn't a direct cause of inboxing problems; it's a signal.
Multifactorial Inboxing: Outlook inboxing rates are influenced by sender reputation, authentication, content, engagement, and other factors.
Authentication Essential: Correctly implementing SPF, DKIM, and DMARC is crucial for sender verification and improved deliverability.

Key considerations

Monitor Status: Monitor Microsoft support channels and community forums for SNDS status updates during reported outages.
Verify Broad Impact: Check with other senders in the industry to confirm whether they are experiencing similar issues to isolate if the problem is unique to your setup.
Proactive Monitoring: Establish proactive monitoring of deliverability metrics beyond SNDS, including bounce rates, complaint rates, and blocklist status.
Authentication Audit: Regularly audit SPF, DKIM, and DMARC configurations to ensure proper implementation and prevent authentication-related deliverability issues.
Address underlying issues: If inbox placement has dropped review reputation, content and engagement metrics to look for underlying issues.

What email marketers say
9Marketer opinions

SNDS outages are a recurring issue often attributed to Microsoft maintenance, updates, or technical problems. While SNDS downtime can coincide with fluctuations in Outlook inboxing rates, a direct causal relationship isn't always clear. Many factors impact inbox placement, including sender reputation, email authentication (SPF, DKIM, DMARC), content quality, user engagement, email volume, and spam complaints. Verifying industry-wide impact and monitoring Microsoft support channels are recommended during outages.

Key opinions

SNDS Downtime: SNDS experiences periodic outages, potentially due to maintenance or technical problems at Microsoft.
Inboxing Impact: While SNDS downtime may coincide with inboxing issues, the link isn't always direct. Other factors are more likely the root cause for inboxing issues.
Multiple Factors: Outlook inboxing rates are affected by various elements, including sender reputation, email authentication, content quality, and user engagement.
Authentication Importance: Properly implementing SPF, DKIM, and DMARC is crucial for verifying sender identity and improving deliverability.

Key considerations

Check Status: Monitor Microsoft support channels for updates on SNDS status during reported outages.
Verify Issue: Check with others in the industry to confirm whether they are also experiencing SNDS downtime and inboxing issues to isolate the problem.
Monitor Deliverability: When SNDS is down monitor deliverability metrics through bounce rates, complaint rates, and block lists.
Review Reputation: Evaluate sender reputation and email authentication to identify and address potential underlying issues impacting inbox placement.

Marketer view

Email marketer from StackOverflow states that email authentication is a critical part of ensuring deliverability. Implement SPF, DKIM, and DMARC correctly to verify your sending identity.

November 2024 - StackOverflow

Marketer view

Marketer from Email Geeks states that SNDS is back today, then later states today I can't see SNDS data again!

July 2024 - Email Geeks

Marketer view

Email marketer from Quora responds that Outlook inboxing rates can be affected by many factors, including IP reputation, authentication (SPF, DKIM, DMARC), content quality, and user engagement. Sudden drops often indicate a problem with one of these areas.

September 2021 - Quora

Marketer view

Email marketer from LinkedIn suggests to check if others in the industry are reporting the same issue to isolate if it is not a specific configuration issue.

July 2021 - LinkedIn

Marketer view

Email marketer from EmailGeek Forum mentions that short term SNDS being down is likely unrelated to inbox placement fluctuation which is more impacted by volume, spam complaints and domain reputation.

September 2021 - EmailGeek Forum

Marketer view

Email marketer from Microsoft Community responds that SNDS outages can occur due to system maintenance, updates, or unforeseen technical issues on Microsoft's side. They advise checking the official Microsoft support channels for updates.

August 2023 - Microsoft Community

Marketer view

Email marketer from Reddit shares that while SNDS data can provide insights, it's not always a direct correlation to inboxing rates. Factors like sender reputation, content, and engagement also play a crucial role.

October 2024 - Reddit

Marketer view

Marketer from Email Geeks shares that SNDS has been down since 6/16 and there has been no response from <mailto:msn-snds@microsoft.com|msn-snds@microsoft.com>. They are also seeing a 20%+ drop in Outlook inboxing for several large retail senders, which seems to have started at the same time SNDS went out.

December 2022 - Email Geeks

Marketer view

Marketer from Email Geeks confirms that SNDS was empty for the last two days.

July 2023 - Email Geeks

What the experts say
3Expert opinions

SNDS outages are frequently caused by Microsoft system maintenance or upgrades, typically temporary but potentially lasting several days. Delays in SNDS data can impact real-time analysis and decision-making. SNDS data is a signal, not a direct cause of inboxing issues; while monitoring SNDS provides valuable insights, manipulating its metrics won't inherently improve inbox placement.

Key opinions

Maintenance Outages: SNDS downtime often stems from scheduled maintenance or upgrades performed by Microsoft.
Data Delays: Data delays within SNDS can hinder the ability to make timely adjustments based on the information.
Signal, Not Cause: SNDS metrics reflect sending practices, but directly altering them won't guarantee better inboxing. SNDS provides insight not direct control.

Key considerations

Expect Downtime: Be prepared for occasional SNDS outages due to maintenance, and factor that into monitoring timelines.
Data Lag: Acknowledge the potential for delays in SNDS data, and avoid making immediate decisions based on potentially outdated information.
Holistic View: Use SNDS data as one component of a broader deliverability monitoring strategy, rather than relying on it as the sole indicator of inboxing health.

Expert view

Expert from Spam Resource explains that SNDS outages are often due to Microsoft performing maintenance or upgrades on their systems. These outages are usually temporary, but can sometimes last for several days.

December 2023 - Spam Resource

Expert view

Expert from Word to the Wise responds that SNDS data is a signal, not a cause. You can’t change your SNDS metrics and cause better inboxing. But if you aren’t watching SNDS you are missing some crucial information.

January 2025 - Word to the Wise

Expert view

Expert from Spam Resource says that there can be delays in SNDS which can affect your view and any action you might take based on that information.

March 2022 - Spam Resource

What the documentation says
4Technical articles

SNDS data reporting may experience delays due to processing times and system load, typically resolving within 24-48 hours. Monitoring patterns in SNDS data, like increased complaints or spam trap hits, can reveal impacts on inbox placement. Comprehensive deliverability monitoring involves tracking bounce rates, complaint rates, and blocklist status. Implementing SPF, DKIM, and DMARC for email authentication is a best practice to improve inbox placement chances.

Key findings

SNDS Data Delays: Processing times and system load can cause delays in SNDS data availability.
SNDS Pattern Analysis: Analyzing patterns in SNDS data (complaints, spam traps) can indicate deliverability impacts.
Holistic Monitoring: Deliverability monitoring should include bounce rates, complaint rates, and blocklist status in addition to SNDS.
Authentication Importance: Implementing SPF, DKIM, and DMARC is recommended for improved inbox placement.

Key considerations

Account for Data Lag: Be aware of potential delays in SNDS data when making decisions.
Proactive Monitoring: Establish proactive monitoring of bounce rates, complaints, and blocklists.
Implement Authentication: Ensure SPF, DKIM, and DMARC are correctly configured for your sending domains.

Technical article

Documentation from SparkPost shares general information about monitoring deliverability through bounce rates, complaint rates, and block lists to see overall impact to deliverability.

October 2024 - SparkPost

Technical article

Documentation from Microsoft details on how to look for patterns of increased complaints, traffic volume, and spam trap hits on SNDS which might reveal impacts on inbox placement.

June 2024 - Microsoft

Technical article

Documentation from Microsoft explains that delays in SNDS data reporting can occur due to processing times and system load. Data is typically available within 24-48 hours, but temporary delays are possible.

March 2022 - Microsoft

Technical article

Documentation from RFC shares that it is best practice to setup SPF, DKIM and DMARC for email authentication in order to improve chances of inbox placement.

May 2021 - RFC

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