Why did Gmail open and click rates decrease after fixing DKIM, despite passing SPF?
Michael Ko
Co-founder & CEO, Suped
Published 27 Apr 2025
Updated 17 Aug 2025
8 min read
It can be incredibly frustrating to see your email open and click rates drop, especially after investing time and effort into fixing critical authentication protocols like DKIM. You've confirmed that SPF is passing, DKIM is now correctly configured, and yet, Gmail recipients aren't engaging as they used to. This scenario is more common than you might think and points to a deeper truth about email deliverability: authentication is necessary, but not sufficient.
The fix might have inadvertently highlighted underlying issues or triggered a re-evaluation of your sending practices by Gmail's sophisticated filtering systems. Understanding this requires looking beyond just SPF and DKIM to the broader spectrum of factors that influence inbox placement and engagement.
Understanding the foundations of email authentication
Sender Policy Framework (SPF) and DomainKeys Identified Mail (DKIM) are foundational pillars of email authentication. SPF verifies that an email originates from a server authorized by the domain owner, while DKIM provides a cryptographic signature that assures the message hasn't been tampered with in transit. Without these, your emails are highly susceptible to being flagged as spam or outright rejected. Gmail's sender guidelines specifically emphasize these protocols as a baseline requirement for deliverability.
When you fix a broken DKIM setup, you're essentially telling mailbox providers that your emails are now trustworthy and verifiable. However, if DKIM was failing for a significant period, your domain's reputation might have suffered. Even if SPF was passing, a consistent DKIM failure can indicate a lack of proper email management, which impacts how providers view your sending practices. Fixing it doesn't instantly erase that historical negative perception.
Domain-based Message Authentication, Reporting, and Conformance (DMARC) builds upon SPF and DKIM by allowing domain owners to specify how recipient servers should handle emails that fail authentication and provides reporting on those failures. Even if you didn't have a DMARC record set up previously, your emails might have been implicitly aligned. Repairing DKIM might have revealed a previous misalignment issue, triggering a shift in how recipient servers evaluate your messages.
The authentication trio
SPF: Lists authorized sending IP addresses for your domain.
DKIM: Digitally signs outgoing emails to prevent tampering.
DMARC: Policy that instructs mailbox providers on how to handle emails based on SPF and DKIM authentication and alignment. It also provides DMARC reports.
Beyond the basics: Gmail's holistic approach to deliverability
While authentication is crucial, it's just one piece of the deliverability puzzle. Mailbox providers, especially Gmail, employ sophisticated algorithms that evaluate numerous signals to determine where an email lands. These signals contribute to your overall sender reputation, and a drop in open and click rates often indicates a dip in this reputation.
Engagement is paramount. If your emails are consistently ignored, marked as spam, or deleted without being opened, it tells Gmail that your content isn't relevant to recipients. Even with perfect SPF and DKIM, low engagement will negatively impact your inbox placement. This could be exacerbated if your previous DKIM failure was masking a deeper engagement problem, which became more apparent once the authentication issue was resolved.
Content quality also plays a significant role. If your email content contains spammy keywords, suspicious links, or lacks clear value, it can trigger spam filters. Large image-to-text ratios, poor formatting, or inconsistent branding can also contribute to lower engagement and spam folder delivery. Even if your authentication is flawless, these content issues can cause a significant drop in deliverability.
Furthermore, your sending patterns matter. Sudden spikes in volume, sending to unengaged lists, or a high bounce rate can signal risky behavior to Gmail. If fixing DKIM coincided with changes in your sending volume or list acquisition, those factors could be contributing to the decline. Mailbox providers are constantly monitoring sender behavior, and any deviation from established positive patterns can lead to a reputation hit. This can explain why open rates might decrease even with correct authentication.
Authentication
Checks: Verifies sender identity (SPF) and message integrity (DKIM).
Purpose: Essential for preventing spoofing and phishing.
Impact: Non-negotiable for getting past initial spam filters. Lack of authentication often leads to immediate rejection or spam folder.
Reputation & engagement
Metrics: Open rates, click rates, spam complaints, unsubscribes, list hygiene, bounce rates.
Purpose: Tells mailbox providers how recipients interact with your emails.
Impact: Directly affects inbox placement, even with perfect authentication. Low engagement leads to spam folder delivery.
Investigating the unexpected drop
To pinpoint the exact reason for the drop, a systematic approach is necessary. Start by leveraging Google Postmaster Tools. Check your domain's reputation, spam rate, and authentication dashboards. A sudden decline in these metrics after fixing DKIM indicates that Gmail's systems are re-evaluating your sending patterns.
Next, review your DMARC reports, if you have them enabled. These XML reports provide granular data on which emails passed or failed SPF and DKIM authentication and how recipients processed them. This can reveal if there's still a configuration issue or if third-party senders are impacting your domain's reputation. If you don't have DMARC reporting configured, now is an excellent time to implement it. You can use a free DMARC record generator tool to get started.
Analyze your email content and list quality. Have there been any changes to your email templates, subject lines, or call-to-actions? Are you sending to an older or less engaged list? High rates of unsubscribes or spam complaints, even without authentication issues, will negatively affect your standing with Gmail. Consider running an email deliverability test using a dedicated tool.
Additionally, check for any unexpected changes in your sending volume or frequency. A sudden increase in email volume after fixing DKIM, especially if sent to a colder list, could trigger spam filters. Also, monitor any potential blacklisting (or blocklisting) of your sending IPs or domain. While less common, being on a blocklist can severely impact deliverability, even with proper authentication. You can utilize a blocklist checker to perform this check.
Factor
Potential impact on deliverability
Content quality
Spammy keywords, broken links, image-heavy layouts lead to spam folders.
Engagement metrics
Low open/click rates, high complaints/unsubscribes signal low recipient interest, affecting inbox placement.
List hygiene
Sending to invalid or unengaged addresses increases bounce rates and spam trap hits.
Sending volume/frequency
Sudden spikes or inconsistent sending can trigger reputation warnings.
Domain and IP reputation
Historical sending behavior, presence on blocklists, and DMARC alignment all contribute.
Strategies for reputation recovery and sustained engagement
Rebuilding domain reputation after a decline takes time and consistent effort. It's not an overnight fix. Mailbox providers, including Gmail, are cautious and will observe your sending behavior over a period before fully restoring your standing. Expect a gradual recovery, not an immediate rebound in open and click rates.
Focus on improving engagement. Segment your audience and send highly relevant content to increase opens and clicks. Implement list cleaning practices to remove unengaged subscribers and invalid email addresses, which can negatively impact your sender score. Regularly monitor your domain reputation metrics to track progress.
Consistency is key. Maintain a regular sending schedule and avoid drastic changes in volume. Gradually increase your sending volume if needed, rather than sending large blasts after a period of low activity. By consistently demonstrating good sending practices, you can steadily rebuild your domain reputation and improve your open and click rates. A helpful resource for increasing your overall deliverability can be found in this email deliverability guide.
Best practices for reputation recovery
Segment your audience: Send highly targeted content to improve engagement metrics.
Clean your lists: Regularly remove inactive subscribers and invalid email addresses.
Monitor actively:Use DMARC monitoring and Postmaster Tools to track deliverability.
Maintain consistency: Keep your sending volume and frequency stable.
Views from the trenches
Best practices
Actively use Google Postmaster Tools to understand how Google views your email sending performance.
Implement DMARC with reporting to gain visibility into authentication failures and email sources.
Focus on maintaining a good sending reputation, which is influenced by multiple factors beyond authentication.
Address any issues related to spoofing or fraudulent activities tied to your domain, as Google considers these in reputation scores.
Not monitoring Google Postmaster Tools regularly for changes in domain reputation.
Ignoring engagement metrics like open rates, click rates, and spam complaints.
Making sudden, large changes to sending volume or list acquisition without warming up.
Expert tips
Remember that Google's domain reputation is a composite score, not solely based on email authentication.
If your domain is associated with issues in Google Search Console or Adwords, it can negatively impact email deliverability.
Poor reputation can lead to reduced data visibility in Google Postmaster Tools.
Recovery from a bad reputation takes time, requiring consistent positive sending behavior.
Expert view
Expert from Email Geeks says Google Postmaster Tools' DMARC metric is based on DMARC alignment, even without an explicit DMARC record. They send DMARC reports only to those with a record.
2023-10-11 - Email Geeks
Expert view
Expert from Email Geeks says Google Postmaster Tools domain reputation is influenced by many signals, not just DKIM verification. The platform can sometimes provide misleading information.
2023-10-11 - Email Geeks
Navigating the complexities of email deliverability
The paradox of decreasing engagement after fixing DKIM, despite passing SPF, highlights the multi-faceted nature of email deliverability. While authentication protocols are fundamental, they are merely the entry ticket to the inbox, not a guarantee of placement.
True deliverability success hinges on maintaining a strong sender reputation, which is built on consistent positive engagement, content quality, and responsible sending practices. Addressing a technical issue like DKIM failure is a crucial step, but it must be followed by a holistic approach to your email program.
By diligently monitoring your metrics, optimizing your content, and prioritizing recipient engagement, you can gradually recover and even surpass your previous open and click rates, ensuring your messages consistently reach the inbox.
