Why has my email open rate dropped suddenly and what can I do?

Key findings

1. Deliverability issues: A significant drop in open rates often signals a problem with email deliverability, meaning your emails are not reaching the inbox as intended.
2. IP reputation: Your sending IP address might be negatively impacting your deliverability, potentially due to being listed on a blocklist (or blacklist), which can lead to emails being filtered to spam.
3. ISP filtering: Changes in ISP filtering algorithms can cause emails to be directed to spam folders or promotional tabs, drastically reducing perceived open rates, especially with major providers like Gmail or Microsoft.
4. Bounce rate anomalies: While lower bounce rates might seem positive, a sudden drop alongside reduced open rates could indicate that emails are not even being attempted by recipient servers, suggesting a deeper blocking issue, as explored in what causes a sudden drop in email open rates.
5. DMARC misconception: Implementing DMARC alone does not directly improve deliverability; its primary function is for authentication and reporting, helping you monitor your email channels.

Key considerations

1. Check Postmaster Tools: Utilise tools like Google Postmaster Tools to identify issues with your domain reputation and see if your emails are being classified as spam. This can offer crucial insight into why your domain reputation is low.
2. Monitor blocklists: Regularly check if your sending IP or domain is listed on any major email blocklists or blacklists, as this is a common cause of sudden deliverability drops. Using a blocklist monitoring service is advisable.
3. Investigate ISP-specific drops: Determine if the open rate decrease is across all ISPs or concentrated at specific ones (e.g., Gmail, Outlook, Yahoo). This can help pinpoint the problem.
4. Engage with ESP support: Your email service provider (ESP) should have tools and insights to help diagnose such issues, especially if the problem is on their shared IP pools.
5. Conduct inbox placement tests: Send test emails to various addresses across different webmail providers to see where your mail is landing (inbox, spam, promotions tab).

Key opinions

1. Unexpected decline: Marketers frequently report sudden, steep drops in open rates even when their sending habits, segmentation, and content remain consistent.
2. Impact on morale: Such unexplainable drops can be highly demoralising, indicating a loss of connection with their audience.
3. ESP-specific issues: Some marketers observe patterns of declining open rates tied to specific ESPs, suggesting internal platform issues or changes in their shared IP reputation, as discussed in communities like ActiveCampaign's forum.
4. Bounce rate vs. open rate: A puzzling observation for some is a drop in open rates accompanied by a simultaneous drop in bounce rates, which can complicate troubleshooting by suggesting mail is being rejected before it can even bounce.
5. Limited ESP analytics: Many ESPs do not provide granular analytics (e.g., specific bounce messages or ISP-level performance) that are crucial for diagnosing complex deliverability issues.

Key considerations

1. Engage ESP support: Marketers are advised to contact their ESP's support team as a first step, as they have access to server-side logs and can investigate IP reputation or other platform-specific issues.
2. Check spam lists: It's important to verify if sending IPs are on any public spam blacklists (or blocklists), even if the ESP is managing them, as this can severely impact inbox placement. You can do this with a blocklist checker.
3. List hygiene: Maintain a healthy email list by regularly removing unengaged contacts, especially if bounce rates have historically been high, as outlined in discussions on HubSpot Community advice.
4. Content review: While not always the primary cause of a sudden drop, marketers should review subject lines and content for freshness and relevance to avoid subscriber fatigue, which can contribute to declining engagement.
5. Authentication check: Ensure proper email authentication, such as SPF, DKIM, and DMARC, is set up, as it can significantly impact deliverability and trustworthiness. More information can be found in our guide to DMARC, SPF, and DKIM.

Key opinions

1. ISP-specific filtering: A drop might be isolated to a single ISP, suggesting that particular provider has started filtering the mail to bulk folders or specific tabs (e.g., Gmail's promotions tab).
2. IP vs. content issues: If mail is being accepted, it's less likely a pure IP reputation problem. Often, it's a 'bulk foldering' issue, which is more about content and sender behaviour than a blacklisted IP, unless the ESP's shared IP is indeed listed, as mentioned in what happens when your domain is put on a blocklist.
3. ESP responsibility for IP issues: For senders using shared IPs through an ESP, any IP-related deliverability problems are almost entirely the ESP's responsibility to fix.
4. DMARC's true purpose: DMARC records are for authentication and reporting, not a direct fix for deliverability. While essential for domain protection, merely having a DMARC TXT record does not inherently improve inbox placement, which is clarified in our DMARC and deliverability guide.
5. Engagement measurement by ISPs: Free webmail providers (Gmail, Microsoft, Verizon) heavily weigh engagement metrics in their filtering decisions, whereas other ISPs (cable providers, business filters) often don't have this visibility.

Key considerations

1. Diagnose ISP-level issues: To pinpoint issues, create test email addresses at various webmail domains and subscribe them to your list. Observe where the emails land (inbox, spam, promotions).
2. Leverage DMARC reports: While DMARC itself doesn't fix deliverability, its reports (RUA/RUF) provide crucial data on authentication failures and sending sources, helping identify if your mail is being sent from blacklisted IPs. Using a DMARC monitoring tool can help interpret these.
3. Understand ISP types: Recognise that different ISPs (free webmail, cable providers, business filters) have varying filtering mechanisms and engagement metrics, which influences their deliverability policies, detailed in articles like why email open rates are still relevant.
4. Proactive ESP communication: If using an ESP, proactively communicate any deliverability concerns, especially sudden drops, as they are best positioned to address shared IP issues or platform-specific configurations affecting your sends.
5. Check for blacklistings: Even if mail is accepted, check the sending IP or domain against RBLs (real-time blocklists) using a blocklist checker, as a listing can still impact inbox placement.

Key findings

1. Authentication standards: Proper implementation of SPF, DKIM, and DMARC is critical for domain reputation and ensuring mailbox providers trust your emails. Failure in any of these can lead to messages being marked as spam.
2. Engagement metrics: Major ISPs (like Gmail and Yahoo) explicitly state that subscriber engagement (opens, clicks) is a key factor in determining inbox placement. A lack of engagement can quickly degrade sender reputation.
3. List hygiene importance: Maintaining a clean email list by removing inactive or invalid addresses is crucial to avoid high bounce rates and spam trap hits, which negatively impact sender score.
4. Content quality: Content that is consistently relevant and provides value helps maintain high engagement rates and avoids spam folder placement.
5. Monitoring Postmaster Tools: Platforms like Google Postmaster Tools provide valuable insights into your domain's reputation, spam rates, and DMARC failures, which are essential for diagnosing deliverability issues, as discussed in our ultimate guide to Google Postmaster Tools.

Key considerations

1. Verify email authentication: Regularly check your SPF, DKIM, and DMARC records to ensure they are correctly configured and aligned with your sending practices. Misconfigurations can lead to emails being rejected or sent to spam, as outlined in documentation on email open rates.
2. Monitor engagement metrics: Pay close attention to changes in open, click, and complaint rates. A sudden drop in opens often precedes a rise in complaints or spam classifications.
3. Implement DMARC policy: Progressively move your DMARC policy from p=none to p=quarantine or p=reject to enforce stricter authentication and protect your domain from spoofing.
4. Segment and re-engage: Segment your list to send to highly engaged subscribers and attempt to re-engage dormant ones before removing them. Sending to unengaged users can harm your overall sender reputation.
5. Review sending infrastructure: If you manage your own IPs, ensure they are not on any public blacklists (or blocklists) and that your sending volume is consistent and within reasonable limits for each IP, a process you can facilitate through blocklist monitoring.