Summary
Many Mailchimp users have recently reported a sudden and significant drop in email open rates, with a corresponding increase in emails being flagged as spam by Gmail. This shift has prompted a community-wide discussion among email marketers and deliverability experts, exploring potential causes ranging from Mailchimp's internal changes to evolving Gmail filtering algorithms. While some attribute the issue to general tightening of inbox placement rules across major mailbox providers, others point to specific authentication or reputation issues tied to Mailchimp's shared IP infrastructure.
Key findings
- Sudden drops: Users reported open rates being cut in half, from typical 30-40% to 5-10%, starting around late May.
- Gmail filters tightening: Many suspect that Gmail has implemented stricter spam filters, affecting emails that previously landed in the inbox. This aligns with a broader trend of mailbox providers (like Yahoo and Outlook) increasing scrutiny.
- Authentication issues: Some users discovered their Mailchimp accounts were using legacy authentication settings, which, when updated, sometimes helped alleviate the problem. Proper email authentication, including SPF, DKIM, and DMARC, is crucial for deliverability.
- Engagement signals: A common theory is that Gmail is becoming stricter with subscribers who do not actively interact (click) with emails, leading to those emails going to spam, even if click-through rates (CTR) remain stable for those who do open.
- Beyond Gmail: The problem was not isolated to Gmail, with reports of failed inbox placement across other major providers like Outlook, Office 365, GoDaddy, Yandex, and Yahoo. This suggests a more systemic issue than just a Mailchimp-specific anomaly.
Key considerations
- Monitor deliverability: Regularly use deliverability testing services to get a broader perspective on inbox placement across various mailbox providers, beyond just personal tests. This can help diagnose sudden drops in open rates.
- Check domain reputation: Even with a perfect domain reputation in Google Postmaster Tools, emails can still land in spam if other factors are at play. However, keeping a close eye on this metric is vital, especially when facing Gmail deliverability issues.
- Proactive list management: Periodically clean your email lists to remove inactive subscribers. Google's move to delete inactive Gmail accounts reinforces the importance of sending to engaged audiences. Mailchimp advises senders to avoid spam filters through practices like maintaining a clean list and relevant content.
- Adapt to new norms: Rather than waiting for ESPs to fix issues, senders should view these changes as a normal evolution of spam filters and adjust their sending strategies accordingly. Focus on quality, engagement, and consistent list hygiene.
What email marketers say
Email marketers using Mailchimp have voiced concerns over unexpected declines in open rates and increased spam folder placement in Gmail. These observations often note a significant drop, sometimes by as much as 50%, with some marketers reporting the issue extending beyond just Gmail to other major mailbox providers. The common thread among these reports is a lack of recent changes in their own sending practices, suggesting external factors are at play, such as evolving filtering rules or shared IP reputation challenges within Mailchimp's ecosystem.
Key opinions
- Widespread impact: Many Mailchimp users observed a sudden and unexplainable drop in open rates, often beginning around the last week of May, affecting multiple accounts simultaneously.
- Engagement discrepancy: Despite halved open rates, click-through rates often remained stable for the emails that did reach the inbox, indicating a filtering issue rather than a content or audience engagement problem. This aligns with findings detailed in articles discussing Mailchimp open rate challenges.
- Multi-provider issue: Spam testing revealed failed inbox placement not only for Gmail but also for Outlook, Office 365, GoDaddy, Yandex, and Yahoo, suggesting a broader problem affecting Mailchimp's overall deliverability.
- Potential IP and account tiering: Speculation arose about whether the issue could be related to Mailchimp's shared IP addresses or how certain tiered accounts (based on contact size or send volume) might be getting flagged.
- Mailchimp's response: Mailchimp acknowledged a change in Gmail's spam filtering leading to more false positives and confirmed they worked with Google to deploy a fix, resulting in open rates bouncing back for some users. This highlights the importance of keeping your email open rate high.
Key considerations
- Authentication updates: Ensure your email authentication (SPF, DKIM) is up-to-date and not using legacy settings, as outdated configurations can significantly hinder deliverability.
- Postmaster tools review: Regularly check Google Postmaster Tools for your domain's reputation. While a perfect domain reputation in Google Postmaster Tools might not guarantee inbox placement, it's a critical indicator of health.
- Strategic list segmentation: When facing deliverability drops, consider scaling back to your most engaged subscribers. This can help rebuild sender reputation and improve overall inbox placement.
- Stakeholder education: Use such deliverability incidents to educate stakeholders on the importance of proper list management, data capture, and sending relevant emails over a more email = more revenue mindset.
Marketer view
Email marketer from Email Geeks observes they have started noticing issues in two separate accounts since the past weekend, with open rates literally cut in half and no recovery since. However, click-through rates for the emails that do get delivered seem to remain about the same, indicating a filtering rather than a content problem.
Marketer view
Email marketer from Email Geeks states that their open rates for Gmail experienced a significant drop from 30-40% down to 5-10% around May 25th or 26th. Personal Gmail addresses are consistently sending emails to the spam folder, while work-related Gmail addresses do not.
What the experts say
Email deliverability experts highlight that fluctuations in email performance, such as drops in open rates and increased spam placement, are often symptomatic of broader shifts in mailbox provider policies rather than isolated incidents. They emphasize the dynamic nature of spam filters and the critical role of sender reputation, list hygiene, and proper authentication. While specific ESPs like Mailchimp might be disproportionately affected by a new filter, the underlying principles of good sending practices remain paramount for maintaining inbox placement across all providers.
Key opinions
- Constant evolution: Experts agree that Gmail filters (and those of other major providers) are constantly evolving. What works today might not work tomorrow, requiring senders to be agile and adapt to new norms.
- Not Mailchimp-specific: While Mailchimp users might experience issues, experts often state that filtering changes are rarely targeted at a single ESP. Instead, they represent a broader tightening of rules that affect senders across different platforms, often related to user engagement signals.
- Engagement is key: Low engagement rates are a significant cause for emails being marked as spam. Mailbox providers prioritize delivering content that users actively interact with, making list hygiene and relevant content crucial for getting messages to the inbox.
- Domain reputation matters: Maintaining a strong domain reputation is foundational. Even if an ESP addresses specific issues, underlying domain reputation problems can lead to ongoing deliverability challenges and can affect how long it takes to recover reputation.
Key considerations
- Proactive monitoring: Implement robust monitoring tools and practices to detect deliverability shifts quickly. Relying solely on open rates (which can be unreliable) is insufficient; analyze broader engagement metrics and inbox placement tests.
- Don't ignore authentication: Ensure SPF, DKIM, and DMARC are correctly implemented and monitored. Mailbox providers increasingly rely on these authentication methods to verify sender legitimacy. Jacob Monash highlights that email providers are actively prompting users to get their DMARC set up properly, indicating a heightened focus on authentication.
- List hygiene is paramount: Regularly remove inactive subscribers, hard bounces, and known spam trap addresses. Sending to unengaged or questionable lists negatively impacts sender reputation and overall deliverability, regardless of ESP.
- Content relevance: Beyond technical factors, ensure your email content remains highly relevant and valuable to your subscribers. Irrelevant content leads to low engagement, increased complaints, and eventual spam folder placement.
- Shared IP risks: Understand that using shared IPs with an ESP means your deliverability can be affected by the sending practices of other users on those same IPs. While standard, persistent issues can indicate systemic problems on the shared network. Mailchimp's resources on dropping open rates and domain reputation can provide further insights.
Expert view
Email expert from SpamResource emphasizes that deliverability issues, including drops in open rates, are rarely isolated to a single ESP. He suggests they often stem from broader changes in how mailbox providers, like Gmail, evaluate sender reputation and user engagement, indicating a need for senders to consistently adhere to best practices.
Expert view
Email expert from Jacob Monash Email Marketing highlights that email providers, including ActiveCampaign and Mailchimp, have actively notified users about setting up email authentication like DMARC. This indicates a growing emphasis on proper sender verification to combat spam and phishing, directly impacting deliverability and open rates.
What the documentation says
Official documentation from email service providers like Mailchimp and mailbox providers like Gmail offers critical insights into email deliverability. They often detail the mechanisms behind open rate tracking, common reasons for emails landing in spam, and best practices for senders. The documentation highlights that factors such as sender reputation, content quality, and proper authentication play a pivotal role in inbox placement. It also advises on actions recipients can take, such as allowlisting, to ensure desired emails are received.
Key findings
- Open tracking mechanisms: Open rates are typically tracked by embedding a small, invisible pixel in emails. When the email is opened and images are loaded, the pixel is triggered, registering an open.
- Spam filter influence: If open rates appear low on reports, it is often a direct result of emails being caught by spam filters. These filters can block the loading of tracking pixels, leading to unrecorded opens even if an email lands in a spam folder.
- Shared server implications: When sending through an ESP like Mailchimp, your emails are delivered via their shared servers. This means that if one user sends spam, it can adversely affect the deliverability for other users on the same servers.
- Authentication management: ESPs offer built-in features to help manage email authentication settings (like SPF and DKIM) to ensure proper verification and improve deliverability. These tools are critical for avoiding email blocklists.
Key considerations
- Recipient allowlisting: For critical emails, documentation often recommends asking contacts to add the sender's email address or the ESP's sending servers to their allowlist. This bypasses many common spam filters.
- Content best practices: Mailchimp's resources on spam triggers advise senders to check their content for elements that could trigger spam filters. This includes excessive imagery, certain keywords, or poor formatting.
- Understanding open tracking limits: Documentation about open tracking explains that the method relies on image loading, meaning opens might not be accurately recorded if recipients have images disabled or if emails are blocked before display.
- Adherence to guidelines: Review and adhere to the ESP's specific guidelines and terms of use, as non-compliance can lead to deliverability issues or account suspension. Mailchimp, like other providers, has strict policies to maintain its shared IP reputation.
Technical article
Documentation from Mailchimp's help center states that if low open rates are observed, it's highly probable that spam filters are the cause. They recommend that senders advise their contacts to allowlist Mailchimp's servers to improve inbox placement and ensure proper open tracking.
Technical article
Documentation from Mailchimp's resources emphasizes that when emails are sent through their servers, the sending practices of one user can impact the deliverability for others. This highlights the collective responsibility in maintaining a healthy shared IP reputation to avoid spam filters.
Related resources
15 resources
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