Why are my email open rates suddenly dropping?

Summary

A sudden drop in email open rates stems from a complex interplay of factors affecting list quality, deliverability, and subscriber engagement. Maintaining a healthy email program requires addressing list hygiene by removing invalid addresses and spam traps, ensuring proper email authentication and monitoring sender reputation, and optimizing content relevance and subject lines. Segmentation, A/B testing, and closely tracking key deliverability metrics provide the insights needed to adapt to changing conditions and maintain consistent subscriber satisfaction. Furthermore, a DMARC failure will cause emails to go to the spam folder, directly impacting open rates.

Key findings

  • List Quality: Poor list quality, including inactive subscribers, spam traps, and invalid addresses, negatively impacts open rates and sender reputation.
  • Deliverability: Deliverability issues, such as emails landing in spam due to poor sender reputation, authentication failures (SPF, DKIM, DMARC), or new spam filters, significantly reduce open rates.
  • Subscriber Engagement: Decreasing subscriber engagement, caused by list fatigue, saturation, or irrelevant content, leads to lower open rates.
  • Content Optimization: Poor subject lines, misleading preview text, and irrelevant content fail to entice subscribers to open emails.
  • Sender Reputation: A damaged sender reputation, often due to spam complaints or policy violations, results in emails being blocked or sent to spam.
  • DMARC Failure: A DMARC failure will cause emails to go straight to the spam folder, directly impacting open rates.
  • Authentication & Routing: Misconfigured email authentication (SPF, DKIM, DMARC) or routing issues can cause deliverability problems and impact open rates

Key considerations

  • List Hygiene: Regularly clean your email list using validation tools to remove invalid addresses and spam traps. Suppress unengaged subscribers to improve overall engagement.
  • Authentication: Implement and properly configure email authentication protocols (SPF, DKIM, DMARC) to improve deliverability and prevent spoofing.
  • Reputation Monitoring: Monitor your sender reputation using tools like Google Postmaster Tools and Microsoft SNDS to identify and address any issues.
  • Content Relevance: Create highly relevant and engaging content tailored to segmented audiences. Test different subject lines and preview text to optimize open rates.
  • Segmentation & Personalization: Segment your email lists based on demographics, interests, and behavior to deliver personalized content that resonates with subscribers.
  • Deliverability Metrics: Track key deliverability metrics (inbox placement, spam complaints, bounce rate) and adjust your strategy accordingly.
  • Permission & Consent: Ensure your email practices comply with permission-based marketing principles and obtain explicit consent from subscribers.

What email marketers say
15Marketer opinions

A sudden drop in email open rates can be attributed to a variety of interconnected factors. These include issues with list quality and hygiene (such as inactive subscribers, spam traps, and bounced emails), deliverability problems (emails landing in spam due to poor sender reputation, authentication failures like DMARC, or new spam filters), and changes in subscriber engagement (list fatigue, saturation of a niche audience, or content irrelevance). Optimizing subject lines and preview text, segmenting email lists for more targeted content, and monitoring key deliverability metrics are also crucial for maintaining healthy open rates.

Key opinions

  • List Quality: Poor list quality, including inactive subscribers, spam traps, and bounced emails, negatively impacts open rates.
  • Deliverability Issues: Deliverability problems like emails landing in spam due to poor sender reputation, authentication failures (DMARC), or new spam filters significantly reduce open rates.
  • Subscriber Engagement: Decreasing subscriber engagement, caused by list fatigue, saturation in niche audiences, or irrelevant content, results in lower open rates.
  • DMARC failures: A DMARC failure will cause emails to go straight to the spam folder causing your open rate to drop
  • Subject Line Optimization: Compelling and relevant subject lines are critical for driving opens.
  • Relevance: New subscribers, changing content, or changing practices will all affect engagement.

Key considerations

  • List Hygiene: Regularly clean your email list by removing inactive subscribers, bounced addresses, and spam traps. Utilize email validation tools.
  • Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) and monitor your sender reputation using tools like Google Postmaster Tools and Microsoft SNDS.
  • Segmentation: Segment your email list to deliver targeted, personalized content based on demographics, interests, and behavior.
  • Content Optimization: Test different subject lines and optimize preview text to improve open rates. Ensure content is relevant and engaging for your audience.
  • Monitoring: Continuously monitor key deliverability metrics such as inbox placement rate, spam complaint rate, and bounce rate to identify and address issues promptly.
  • Permission: Email is permission-based and relies on consistent subscriber satisfaction.
Marketer view

Email marketer from Email Geeks explains that determining exact spam folder placement is difficult and requires relying on signals like low complaints combined with low opens. They emphasize the need to increase positive engagement (opens, clicks, replies, moving emails to inbox) regardless of whether emails land in the inbox or spam folder.

August 2021 - Email Geeks
Marketer view

Email marketer from ReturnPath shares that monitoring email deliverability metrics is essential for identifying and addressing issues that can impact open rates. They recommend tracking metrics such as inbox placement rate, spam complaint rate, and bounce rate to gain insights into your email deliverability performance. These insights can help you optimize your email marketing strategy and improve your open rates.

August 2022 - ReturnPath
Marketer view

Email marketer from Email Geeks shares potential reasons for dropping open rates which can include sending to a specific provider or overall, sending to more or different people than usual, message clipping preventing open pixel loading, delays/blocks/complaints, authentication changes, and spam folder placement. They suggest checking email headers and investigating deliverability issues.

September 2022 - Email Geeks
Marketer view

Email marketer from Warrior Forum shares the potential for a new spam filter impacting deliverability. They explained that new rules by mailbox providers or being blacklisted could be the reason. They suggest checking if their IP address or domain has been blacklisted.

November 2021 - Warrior Forum
Marketer view

Email marketer from Sendinblue explains that proper segmentation is crucial for improving email engagement and open rates. They recommend segmenting your email list based on demographics, interests, and behavior to target subscribers with relevant content. Personalized emails are more likely to be opened and engaged with.

August 2022 - Sendinblue
Marketer view

Email marketer from Litmus shares the importance of subject line optimization for improving email open rates. They recommend testing different subject lines to identify which ones resonate best with your subscribers. Avoid using spammy keywords or misleading language, and ensure that your subject lines accurately reflect the content of your email.

October 2022 - Litmus
Marketer view

Email marketer from Reddit explains that sometimes open rates drop when the audience is very niche. They explain that this can be due to saturation or the audience simply not being interested anymore. They suggest cleaning the list and running new campaigns to generate interest.

June 2021 - Reddit
Marketer view

Email marketer from Email Geeks explains a DMARC failure due to a typo in the DMARC record caused a significant drop in open rates. Alison Gootee further explains that a DMARC failure would cause emails to go to the spam folder, thus impacting open rates.

November 2021 - Email Geeks
Marketer view

Email marketer from ZeroBounce emphasizes the importance of using email validation tools to ensure the accuracy and deliverability of your email list. They recommend using email validation services to identify and remove invalid email addresses, reducing bounce rates and improving sender reputation. High bounce rates can negatively impact your open rates.

March 2024 - ZeroBounce
Marketer view

Email marketer from Email Geeks suggests checking if emails are clipped and investigating spam complaints within the ESP. They advise focusing on user acquisition/targeting and content, ensuring voluntary sign-ups with double opt-in. Furthermore, they recommend aligning content with expectations, managing email frequency, and ensuring easy unsubscription. Alison emphasizes the importance of generating positive engagement and understanding subscriber behavior to improve email outcomes, suggesting reducing volume and focusing on highly engaged users in the short term.

January 2023 - Email Geeks
Marketer view

Email marketer from HubSpot explains the potential impact of list fatigue, which occurs when subscribers become less interested in your emails over time. This can lead to lower open rates and engagement. HubSpot recommends segmenting your list to target subscribers with relevant content and removing inactive subscribers to improve overall list quality. Also content relevancy can be an issue and needs to be addressed.

January 2025 - HubSpot
Marketer view

Email marketer from SparkPost explains that poor list hygiene practices can significantly impact email open rates. They recommend regularly cleaning your email list by removing inactive subscribers, bounced email addresses, and spam traps. Maintaining a clean email list helps improve your sender reputation and ensures that your emails reach engaged subscribers.

July 2021 - SparkPost
Marketer view

Email marketer from Campaign Monitor shares to investigate recent changes in your email marketing strategy, such as changes in sending frequency, subject lines, or content. They suggest comparing your recent campaigns with previous ones to identify any significant differences. Additionally, they recommend checking your sender reputation and authentication settings (SPF, DKIM, DMARC) to ensure deliverability.

January 2022 - Campaign Monitor
Marketer view

Email marketer from Email on Acid recommends optimizing email preview text to encourage opens. They suggest that crafting compelling preview text, which is the snippet of text that appears below the subject line in many email clients, can significantly improve open rates. It provides additional context and entices subscribers to open the email.

April 2023 - Email on Acid
Marketer view

Email marketer from Mailchimp explains that several factors can affect your email open rates. These include changes in subscriber engagement, list quality issues (such as inactive subscribers or spam traps), deliverability problems (such as emails going to spam), and content relevance. A sudden drop could indicate a problem in one or more of these areas.

August 2021 - Mailchimp

What the experts say
2Expert opinions

Declining email open rates are primarily due to changes affecting list quality, content relevance, or sender reputation. Maintaining good list hygiene by removing invalid email addresses, regularly validating email lists, and ensuring emails are permission-based is crucial. Consistent subscriber satisfaction and engagement are vital for sustained open rates. The type of email sent, whether marketing or transactional, can also significantly impact deliverability and open rates.

Key opinions

  • List Quality: Invalid email addresses and poor list quality negatively affect deliverability and open rates.
  • Engagement Metrics: Changes in engagement metrics, including open rates, are almost always due to a change in list, content, or reputation.
  • Permission-Based: Email marketing relies on consistent subscriber satisfaction and adherence to permission-based practices.
  • Email Type: The type of email send (marketing or transactional) can impact deliverability.

Key considerations

  • List Validation: Regularly validate email addresses to remove invalid ones and maintain list hygiene.
  • List Cleaning: Clean your email lists to improve deliverability and engagement.
  • Subscriber Satisfaction: Focus on maintaining consistent subscriber satisfaction to improve email open rates.
  • Reputation Monitoring: Monitor sender reputation to identify and address any negative changes affecting deliverability.
Expert view

Expert from Word to the Wise Staff explains the effect of invalid email address on the delivery and open rates. They indicate list quality and the type of email send (marketing or transactional) can have negative effects. They suggest sending email validation regularly and cleaning lists.

January 2023 - Word to the Wise
Expert view

Expert from Spam Resource, Laura Atkins, explains that declining engagement metrics, including open rates, are almost always due to a change in list, content, or reputation. New subscribers, changing content, or changing practices will all affect engagement. She emphasizes that email is permission-based and relies on consistent subscriber satisfaction.

February 2023 - Spam Resource

What the documentation says
4Technical articles

A sudden drop in email open rates can be due to poor sender reputation, email authentication issues, or improper email header formatting. Monitoring your IP and domain reputation with tools like Google Postmaster Tools and Microsoft SNDS is crucial. Implementing DMARC can protect your domain from spoofing and phishing and improve deliverability. Analyzing email headers according to RFC 5322 standards can help identify authentication and routing issues that impact open rates.

Key findings

  • Sender Reputation: Maintaining a good sender reputation is crucial for email deliverability; sudden drops can indicate spamming or policy violations.
  • Email Authentication: Issues with email authentication (SPF, DKIM, DMARC) can cause deliverability problems and impact open rates.
  • Header Formatting: Improperly formatted email headers can lead to emails being filtered as spam.
  • DMARC Implementation: Implementing DMARC protects your domain from spoofing and phishing and improves email delivery.

Key considerations

  • Reputation Monitoring: Monitor IP and domain reputation using Google Postmaster Tools and Microsoft SNDS.
  • Authentication Setup: Implement and maintain proper email authentication (SPF, DKIM, DMARC).
  • Header Analysis: Analyze email headers for proper formatting and potential routing issues according to RFC 5322.
  • DMARC Configuration: Properly configure DMARC to protect your domain and improve deliverability.
Technical article

Documentation from Google Postmaster Tools explains that maintaining a good sender reputation is crucial for email deliverability. They advise monitoring your IP reputation and domain reputation in Postmaster Tools to identify any potential issues that could be affecting your open rates. Sudden drops in reputation can indicate spamming activity or other policy violations.

June 2022 - Google Postmaster Tools
Technical article

Documentation from DMARC.org explains that DMARC (Domain-based Message Authentication, Reporting & Conformance) is an email authentication protocol that helps protect your domain from email spoofing and phishing attacks. Implementing DMARC can improve your sender reputation and ensure that your emails are delivered to the inbox, improving open rates.

March 2024 - DMARC.org
Technical article

Documentation from Microsoft SNDS explains that Microsoft's Smart Network Data Services (SNDS) allows you to monitor your IP reputation and identify potential issues that could be affecting your email deliverability to Outlook.com and Hotmail users. They advise checking SNDS regularly for any changes in your IP reputation or complaint rates, which can impact open rates.

November 2022 - Microsoft SNDS
Technical article

Documentation from RFC 5322 explains the structure of email headers and the importance of proper formatting. They advise analyzing email headers to identify any potential issues with authentication (SPF, DKIM, DMARC) or routing that could be causing deliverability problems and impacting open rates. Incorrectly formatted headers can lead to emails being filtered as spam.

December 2022 - RFC Editor


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