Why is Google Postmaster Tools (GPT) showing incorrect SPF and DKIM authentication rates?

Key findings

• Data anomalies: Users frequently report seeing SPF and DKIM rates drop to 0% or show N/A for DMARC, despite knowing their authentication is correctly configured.
• Fluctuating rates: Authentication rates can jump dramatically between 0% and 100% for SPF and DMARC, while DKIM may remain consistently at 100%.
• No delivery impact: Often, these reported issues in GPT do not correspond to actual email delivery problems or inbox placement changes.
• Data lag: A common explanation for initial incorrect readings is a delay in data processing and aggregation within GPT.
• GPT updates: Speculation suggests that Google's ongoing rollout of new Postmaster Tools versions may occasionally disrupt the data feeds into the current dashboard, causing temporary glitches.

Key considerations

• Verify configurations: Always independently check your SPF, DKIM, and DMARC records to ensure they are correctly set up and aligned.
• Monitor over time: Do not panic over single-day anomalies. Instead, focus on longer-term trends and consistency in the data. For more on GPT's data, read our guide on why GPT data is glitchy and inconsistent.
• SPF alignment: Ensure your SPF domain aligns with your From header domain for DMARC to pass, as this can affect how GPT reports SPF results. Read Mailgun's updates to authentication monitoring for more.
• Return-path and custom DKIM: Confirm that your sender is using a customized return-path and custom DKIM, as these are critical for proper authentication and GPT reporting.
• Conflicting results: Be aware that email deliverability tools and Postmaster Tools can sometimes report conflicting authentication results. You can find more information about this at why deliverability tools report conflicting results.

Key opinions

• Widespread issue: Multiple marketers confirm seeing widespread instances of 0% SPF/DKIM and N/A DMARC data for the same period.
• No panic advised: If email headers are known to be good and authentication is passing elsewhere, it's generally recommended not to panic immediately.
• Sudden crisis alarm: Incorrect GPT data can lead marketers down a rabbit hole of troubleshooting, believing there's a sudden authentication crisis.
• No configuration changes: Many marketers report no recent DNS record changes, indicating the issue lies with GPT's reporting, not their setup.
• No delivery impact: Despite GPT showing issues, customer domains often still show 100% authentication, and no actual delivery problems are observed. You can learn more about this in our article: why GPT shows authentication failures.

Key considerations

• Cross-verification: Always verify your SPF and DKIM authentication status using independent tools and direct email header analysis, rather than relying solely on GPT's dashboard. Ensure that you also check your SPF success rate in GPT.
• Patience: Allow sufficient time (24-48 hours) for GPT data to fully populate and stabilize before drawing conclusions.
• Avoid over-troubleshooting: Do not chase phantom issues indicated by potentially glitchy data if other sources confirm your authentication is working.
• Communicate with clients: If clients notice discrepancies, reassure them that Postmaster Tools can be erratic and not always reflect real-time deliverability. Refer to Growleads' insights on sender reputation.
• Monitor trends: Focus on the overall trend of your authentication rates rather than day-to-day fluctuations.

Key opinions

• Data loading issues: Experts suggest that GPT data often experiences delays in populating completely, which can lead to temporary inaccuracies in reported authentication rates.
• SPF alignment: An email authentication expert notes that the SPF result in GPT may appear to fail if the SPF alignment for DMARC is not met, even if SPF passes technically.
• Development on production: Some experts speculate that Google's rollout of new Postmaster Tools might be causing current data feeds to be b0rked, suggesting a potential live environment issue.
• Not a real crisis: If underlying authentication checks out through other means, temporary GPT anomalies are usually not indicative of a true authentication crisis.
• Volume consistency: Experts consider whether sending volume to Gmail is consistent daily, as this can sometimes influence how data is reported in Postmaster Tools.

Key considerations

• Focus on alignment: Prioritize DMARC alignment for both SPF and DKIM, as GPT heavily relies on this for its reporting of authentication success rates. Learn more about DMARC, SPF, and DKIM.
• Independent verification: Always use external tools or direct email header analysis to confirm your authentication status. Consult Server Fault's discussion on SPF failures.
• Anticipate changes: Be aware that Google frequently updates its tools, which can cause temporary data disruptions. For example, GPT reports SPF failures for ActiveCampaign sends sometimes.
• Educate clients: Inform clients that GPT data can be erratic and may not always reflect real-time deliverability or actual issues.
• Investigate sending patterns: If fluctuations persist, investigate whether they correlate with inconsistent sending volumes or varied sending methods (e.g., transactional vs. marketing emails).

Key findings

• Data scope: Google Postmaster Tools only reports on messages that Google successfully associates with a domain via either SPF or DKIM, as highlighted by SocketLabs' documentation.
• Authentication dashboard: The authentication dashboard provides the percentage of emails that passed SPF, DKIM, and DMARC tests, according to Netcore CPaaS User Guide.
• DMARC alignment impact: SPF results in GPT can appear to fail if DMARC alignment is not met, even if SPF passes technically, as discussed in ServerFault threads.
• Data update frequency: GPT updates its data relatively quickly, typically within 24 hours after any configuration changes.
• New dashboards: Google has introduced new dashboards in GPT that provide more detailed information on potential delivery errors, authentication (SPF, DKIM, DMARC), and TLS encryption.

Key considerations

• Understand GPT's scope: Recognize that GPT data is specific to Gmail's perception and processing of your emails and may not fully align with other monitoring tools. Check SocketLabs' Postmaster Tools blog.
• Ensure DMARC alignment: Proper DMARC alignment is crucial for SPF and DKIM authentication to be reported correctly in GPT, as a misaligned SPF may appear as a failure. Understand DMARC tags and their meanings.
• Verify DNS records: Correct setup of SPF and DKIM DNS records is foundational for authentication and accurate reporting in GPT. Learn what the full form of SPF is.
• Interpret N/A: An 'N/A' (not available) status for DMARC in GPT often means there wasn't enough volume for data to populate or that authentication failed entirely, rather than a data error.
• Leverage all dashboards: Utilize all available GPT dashboards (reputation, spam rate, delivery errors, encryption) to get a comprehensive view of your email program's health, as described by the Netcore CPaaS User Guide.