What could be causing email delivery problems to Gmail despite consistent open rates?

Summary

Email delivery problems to Gmail, despite consistent open rates, can arise from a multitude of factors. While consistent opens suggest initial inbox placement, issues like poor sender reputation (due to spam complaints or blacklisting), misconfigured email authentication (SPF, DKIM, DMARC), problematic email content triggering spam filters, poor list hygiene with invalid/inactive addresses or spam traps, low engagement metrics beyond opens, and a newly established or rapidly scaled IP address affecting IP reputation can all negatively impact deliverability. Furthermore, the volume of unengaged subscribers ('greymail') sends signals to Gmail that the content is less relevant. Gmail FBL data comes from GPT, which is less relevant to Google problems. Lastly, the actual inbox placement (spam vs. inbox) can't be determined solely by open rates, so inbox placement testing is essential, as is monitoring Microsoft Smartscreen. Compliance with Google bulk sending guidelines is paramount.

Key findings

  • Sender Reputation: Flagged domains due to complaints/blacklisting affect Gmail filtering.
  • Authentication: Incorrect SPF, DKIM, DMARC cause suspicion, leading to filtering.
  • Content Issues: Spammy content triggers Gmail's filters regardless of open rates.
  • List Hygiene: Invalid/inactive addresses and spam traps on lists harm deliverability.
  • Engagement: Low replies, forwards, and clicks result in filtering.
  • IP Reputation: New IPs or rapid sending volume increases can negatively affect IP reputation.
  • Inbox Placement: Open rates don't guarantee inbox delivery; placement tests are needed.
  • Greymail: High proportion of unengaged subscribers negatively impact deliverability
  • FBL Data: Gmail FBL data comes from GPT
  • SmartScreen: Microsoft's SmartScreen can block emails due to content/sending patterns.
  • Google Guidelines: Not following Google's sender guidelines affects deliverability.

Key considerations

  • Reputation Monitoring: Regularly check and address sender reputation and spam complaints.
  • Authentication Setup: Ensure correct SPF, DKIM, and DMARC setup and validation.
  • Content Optimization: Optimize content to avoid spam triggers and excessive elements.
  • List Cleaning: Regularly clean lists to remove invalid/inactive emails and spam traps.
  • Engagement Focus: Create compelling content to boost replies, forwards, and clicks.
  • IP Warm-up Strategy: Implement a gradual IP warm-up strategy for new IP addresses.
  • Deliverability Testing: Conduct inbox placement testing to monitor inbox vs. spam delivery.
  • Engagement Segmentation: Segment subscribers based on engagement and tailor messaging accordingly.
  • SmartScreen Monitoring: Monitor SmartScreen data and adjust content/sending as needed
  • Adhere to Google Guidelines: Ensure compliance with Google's bulk sending best practices.

What email marketers say
7Marketer opinions

Despite consistent open rates, email delivery problems to Gmail can stem from various factors beyond whether subscribers are opening emails. These include issues with sender reputation due to spam complaints or blacklisting, misconfigured email authentication protocols (SPF, DKIM, DMARC), problematic email content that triggers spam filters, poor list hygiene with invalid or inactive addresses, low engagement metrics beyond opens (replies, forwards, clicks), a newly established or rapidly scaled IP address affecting IP reputation, and the actual inbox placement (spam vs. inbox) which open rates alone cannot determine.

Key opinions

  • Sender Reputation: Domain flagging due to complaints/blacklisting impacts Gmail filtering.
  • Authentication Issues: Incorrectly configured SPF, DKIM, DMARC can cause suspicion.
  • Content Triggers: Spammy content elements can activate Gmail's filters.
  • List Hygiene: Invalid/inactive emails harm deliverability despite opens.
  • Engagement Metrics: Low replies, forwards, clicks lead to filtering.
  • IP Reputation: New IP or increased volume negatively affect reputation.
  • Inbox Placement: Open rates don't guarantee inbox delivery; test placement.

Key considerations

  • Monitor Reputation: Regularly check sender reputation and address complaints.
  • Verify Authentication: Ensure SPF, DKIM, and DMARC are correctly set up.
  • Optimize Content: Avoid spammy keywords, excessive images, large attachments.
  • Cleanse Email List: Remove invalid/inactive addresses to improve engagement.
  • Encourage Engagement: Focus on content that prompts replies, forwards, clicks.
  • Manage IP Warm-up: Gradually increase sending volume with a new IP address.
  • Test Deliverability: Use inbox placement tools to check inbox vs. spam folder delivery.
Marketer view

Email marketer from Mailjet explains that Gmail could be filtering emails despite open rates if email authentication protocols like SPF, DKIM, and DMARC are not correctly configured. This can cause Gmail to view emails with suspicion.

July 2021 - Mailjet
Marketer view

Email marketer from GlockApps explains that inbox placement testing is the most important thing to check to see if you are landing in the inbox, promotion tab, or spam folder. You can't just rely on open rates alone.

May 2022 - GlockApps
Marketer view

Email marketer from NeilPatel.com explains that sender reputation problems can occur even with consistent open rates if your domain has been flagged due to spam complaints or blacklisting. This can impact Gmail's filtering.

February 2024 - NeilPatel.com
Marketer view

Email marketer from Gmass responds that even with high open rates a new IP address, a sudden increase in sending volume, can negatively impact IP reputation, leading to emails being filtered.

November 2021 - Gmass
Marketer view

Email marketer from Sendinblue explains that even with good open rates, your email content may contain elements that trigger Gmail's spam filters (e.g., spammy keywords, excessive use of images, or large attachments).

February 2023 - Sendinblue
Marketer view

Email marketer from EmailGeek Forum responds that Gmail looks at more than just open rates; it also considers engagement metrics like replies, forwards, and clicks. If those are low, Gmail might filter emails even if open rates are okay.

October 2022 - EmailGeek Forum
Marketer view

Email marketer from Reddit shares that consistent open rates don't negate the importance of a clean email list. If Gmail identifies a high number of invalid or inactive email addresses on your list, it may impact your deliverability to active subscribers.

April 2021 - Reddit

What the experts say
5Expert opinions

While consistent open rates might suggest emails are reaching the inbox and pixels are being pre-fetched, deliverability issues with Gmail can still arise. GPT reputation is a lagging indicator. Google doesn't send FBLs directly; data comes from GPT, though this is less relevant to Google-specific problems. Furthermore, 'greymail' (unengaged subscribers) can negatively impact deliverability, as Gmail interprets low engagement as irrelevance. Finally, using outdated or purchased email lists, even in small quantities, introduces spam traps and invalid addresses, which can lead to filtering.

Key opinions

  • Open Rates & Initial Delivery: Consistent open rates indicate initial inbox placement and pixel pre-fetching.
  • GPT Reputation: GPT reputation is a trailing indicator of deliverability.
  • FBL Data Source: Google FBL data comes directly from GPT, not Google.
  • Greymail Impact: Unengaged subscribers (greymail) lower overall deliverability.
  • List Quality: Outdated or purchased lists introduce spam traps and invalid addresses, harming deliverability.

Key considerations

  • IP Reputation Focus: Monitor IP reputation alongside open rates.
  • Engagement Segmentation: Segment and engage with active subscribers separately from unengaged ones.
  • List Hygiene Practices: Regularly clean and validate email lists to remove invalid addresses and spam traps.
  • Monitor GPT Data: Track GPT data and address issues.
Expert view

Expert from Email Geeks explains that consistent open rates suggest Gmail is still putting emails in the inbox and pre-fetching pixels. She then asks about the concern regarding IP reputation and whether the user is on a dedicated or shared IP.

December 2024 - Email Geeks
Expert view

Expert from Word to the Wise explains that even if a segment of subscribers consistently open emails, a large portion of unengaged subscribers (greymail) can negatively impact deliverability with Gmail, because Gmail's algorithm interprets lack of engagement as a signal that the sender isn't relevant.

December 2024 - Word to the Wise
Expert view

Expert from Spamresource.com shares that even if some subscribers open your emails, outdated or purchased lists (even small amounts) will likely have spam traps and invalid addresses, which Google is likely to identify leading to filtering.

January 2025 - Spamresource.com
Expert view

Expert from Email Geeks clarifies Google doesn’t send a FBL, and the data must come directly from GPT, which is not relevant to a Google problem.

November 2024 - Email Geeks
Expert view

Expert from Email Geeks shares that GPT reputation tends to be a trailing factor for delivery, and she doesn’t see much problem with reaching the inbox.

August 2021 - Email Geeks

What the documentation says
4Technical articles

Even with consistent open rates, email delivery to Gmail can be hindered by not adhering to Google's bulk sender guidelines. This includes proper subscription list management, easy unsubscribe options, and correct email formatting. Furthermore, incorrect or missing SPF records can lead to authentication failures, impacting deliverability. A failing DMARC policy, which instructs email providers on handling unauthenticated emails, can cause rejections. Lastly, Microsoft's SmartScreen filter might block emails if content or sending patterns resemble spam, regardless of open rates.

Key findings

  • Google Guidelines: Failure to follow Google's bulk sender guidelines affects filtering.
  • SPF Records: Missing or misconfigured SPF records cause authentication failures.
  • DMARC Policy: Failing DMARC policy can lead to email rejection or filtering.
  • SmartScreen Filter: Microsoft's SmartScreen blocks spam-like content/patterns.

Key considerations

  • Adhere to Guidelines: Comply with Google's bulk sender best practices.
  • Verify SPF Configuration: Ensure correct SPF record setup for email authentication.
  • Implement DMARC Policy: Establish a robust DMARC policy to manage unauthenticated emails.
  • Monitor SmartScreen: Be mindful of content and sending patterns to avoid triggering SmartScreen.
Technical article

Documentation from Microsoft explains that Microsoft's SmartScreen filter might be blocking emails if your content or sending patterns resemble those of spammers, regardless of open rates.

September 2023 - Microsoft
Technical article

Documentation from Google Support explains that Gmail filters can be affected if you're not following Google's bulk sender guidelines, including properly managing subscription lists, providing easy unsubscribe options, and formatting emails correctly.

January 2023 - Google Support
Technical article

Documentation from DMARC.org explains that DMARC policies provide instructions to email providers on how to handle unauthenticated emails. A failing DMARC policy can cause Gmail to reject or filter emails, despite good open rates from existing recipients.

January 2025 - DMARC.org
Technical article

Documentation from RFC explains that an improperly configured or missing SPF record can cause emails to fail authentication checks, leading to deliverability issues with Gmail, even if open rates appear normal.

September 2021 - RFC