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Why is Gmail blocking my emails despite high reputation in Google Postmaster Tools?

11 Marketer opinions3 Expert opinions4 Technical articles2 Resources

Summary

Even with a high reputation in Google Postmaster Tools (GPT), Gmail may still block emails due to a multitude of factors. These factors encompass technical aspects such as proper email authentication (SPF, DKIM, DMARC), rDNS configuration, and shared IP reputation. Furthermore, Gmail's complex filtering algorithms consider user engagement, complaint rates, spam trap hits, and content-related triggers (spam-like keywords, poor formatting, URL shorteners). Sending practices like inconsistent volume, sudden spikes, and the use of purchased lists also affect deliverability. Data delays in GPT can lead to discrepancies between reported reputation and actual filtering decisions. Ultimately, a high reputation does not guarantee inbox placement; a holistic approach is needed.

Key findings

  • GPT Data Delays: Postmaster Tools data may not reflect real-time deliverability issues due to processing delays.
  • Authentication is Critical: Proper email authentication (SPF, DKIM, DMARC) is essential for Gmail deliverability, even with a good reputation.
  • Engagement Matters Most: Gmail prioritizes user engagement; low engagement rates can lead to blocking despite a positive reputation.
  • Content and Structure: Email content (keywords, formatting, links) and HTML coding contribute significantly to spam filtering decisions.
  • Sending Practices Impact Reputation: Inconsistent sending volumes, sudden spikes, and the use of purchased lists negatively affect deliverability.
  • Complex Algorithm: Gmail employs a complex filtering algorithm considering many factors beyond simple reputation scores.
  • Complaint Impact: High spam complaint rates severely impact deliverability, overriding positive reputation signals.
  • Shared IP Risks: Shared IP addresses and their overall reputation influence deliverability; the actions of others on the IP impact your deliverability.

Key considerations

  • Monitor Technical Configuration: Regularly audit and maintain proper SPF, DKIM, and DMARC records to ensure correct authentication.
  • Improve Engagement: Focus on building a highly engaged subscriber base with content that resonates with your audience.
  • Manage Sending Volume: Avoid sudden volume spikes and implement a gradual warm-up strategy for new domains or IP addresses.
  • Clean Your Lists: Regularly prune inactive or unengaged subscribers to maintain high engagement rates.
  • Avoid Spam Triggers: Carefully review email content for spam-like keywords, misleading subject lines, and broken links.
  • Monitor Complaint Rates: Actively monitor feedback loops and unsubscribe requests to address and mitigate high complaint rates.
  • Check IP Reputation: Assess the IP reputation to see if it's negatively impacting email delivery.
  • Review Content: Examine email content for spam-like keywords, poor formatting, or broken links.
  • Warm Up IP: Test it with your own addresses initially. If mail goes through, re-warm up your domain starting with the most engaged users.

What email marketers say
11Marketer opinions

Even with a high reputation in Google Postmaster Tools, Gmail may still block emails due to several factors beyond overall reputation. These include delays in Postmaster Tools data updates, content triggers in the email itself (such as spam-like keywords or poor formatting), inconsistent sending practices, sudden volume spikes, issues with new sending domains, high complaint rates, improper list management, the use of URL shorteners or spam phrases, poor HTML coding, and the use of purchased email lists. Monitoring IP reputation and email authentication is also important.

Key opinions

  • Data Delays: Google Postmaster Tools data may not be real-time, so recent sending behavior can impact deliverability before the reputation updates.
  • Content Triggers: Gmail filters based on content, including spam-like keywords, poor formatting, and broken links, regardless of sender reputation.
  • Sending Consistency: Inconsistent sending practices and sudden volume spikes can trigger Gmail's filters, overriding a good reputation.
  • Complaint Rates: High complaint rates override any high reputation, as Gmail considers user feedback a major filtering factor.
  • List Management: Improper list management, leading to low engagement and higher bounce rates, can negatively impact deliverability.
  • URL Shorteners & Spam Phrases: Emails may be caught by spam filters for using URL shorteners or common 'spam' phrases.
  • HTML Coding: Poor HTML coding practices can cause an email to be marked as spam.
  • Purchased Lists: Using purchased email lists significantly damages sender reputation, even with a high IP reputation.
  • New Sending Domain: If the sending domain is new it might still be impacted by reputation especially if the domain hasn't been fully validated with authentication methods.

Key considerations

  • Monitor GPT: Continuously monitor Google Postmaster Tools, but be aware of potential data delays.
  • Content Review: Regularly review email content for spam triggers and ensure proper formatting.
  • Gradual Warmup: Implement a gradual warmup process, especially when starting with a new domain or after periods of inactivity.
  • Feedback Loop: Actively monitor complaint rates and address any negative feedback promptly.
  • List Hygiene: Maintain strict list hygiene practices to ensure high engagement and low bounce rates.
  • Code Quality: Ensure HTML code is clean and follows best practices to avoid being flagged as spam.
  • Avoid Purchased Lists: Never use purchased email lists, as they can severely damage sender reputation.
  • Authenticate Email: Fully validate the sending domain with authentication methods.
  • Monitor IP Reputation: Check the IP reputation to see if they are being used for the outgoing emails triggering the bounces.
Marketer view

Email marketer from Quora states that high complaint rates override any high reputation. Gmail monitors user feedback and considers complaints a major factor in filtering decisions.

June 2023 - Quora
Marketer view

Email marketer from Litmus explains that the emails might be getting caught by spam filters for using URL shorteners or common 'spam' phrases. Review your email content carefully.

March 2024 - Litmus
Marketer view

Email marketer from Campaign Monitor explains that using purchased email lists significantly damages sender reputation, even if you have a high IP reputation. Avoid purchased lists.

August 2023 - Campaign Monitor
Marketer view

Email marketer from Reddit shares that Gmail might be filtering based on content triggers, even with a good sending reputation. Examine email content for spam-like keywords, poor formatting, or broken links.

September 2024 - Reddit
Marketer view

Email marketer from Stack Overflow shares that if the sending domain is new it might still be impacted by reputation especially if the domain hasn't been fully validated with authentication methods.

June 2022 - Stack Overflow
Marketer view

Marketer from Email Geeks explains that Postmaster data might be delayed by approximately two days. The SMTP responses might be triggered by a recent event.

May 2022 - Email Geeks
Marketer view

Email marketer from Mailgun Blog responds that inconsistent sending practices or sudden volume spikes can trigger Gmail's filters, overriding a previously good reputation. Gradual warmup is recommended.

December 2024 - Mailgun Blog
Marketer view

Email marketer from Email on Acid shares that issues might arise from improper list management, leading to low engagement and higher bounce rates. Good list hygiene practices are important even with high reputation.

October 2021 - Email on Acid
Marketer view

Email marketer from EmailGeek Community suggests that the Google Postmaster Tools data may not be real-time, and the high reputation shown might be a delayed reflection. Recent sending behavior could still be impacting deliverability.

September 2024 - EmailGeek Community
Marketer view

Marketer from Email Geeks suggests checking the IP reputation in GPT to see if they are being used for the outgoing emails triggering the bounces.

March 2022 - Email Geeks
Marketer view

Email marketer from SendGrid explains that deliverability problems might be due to the email's HTML code. Poor coding practices can cause an email to be marked as spam.

January 2025 - SendGrid

What the experts say
3Expert opinions

Even with a high reputation in Google Postmaster Tools (GPT), Gmail can block emails due to a combination of factors. Proper technical configuration, including rDNS, SPF, DKIM alignment, is crucial. Focusing on engagement metrics by sending engaging content to active users helps maintain a healthy sender reputation. Gmail's complex filtering algorithms also consider user complaints, spam trap hits, and other negative signals, so a high reputation alone doesn't guarantee inbox placement.

Key opinions

  • Technical Configuration: Correct rDNS, SPF, and DKIM alignment are crucial technical factors influencing deliverability.
  • Engagement Metrics: Gmail considers engagement metrics as a primary factor, therefore sending engaging content is crucial.
  • Complex Filtering: Gmail's filtering considers user complaints, spam trap hits, and numerous other signals, meaning reputation isn't the only determining factor.

Key considerations

  • Address Technical Issues: Check and correct technical configuration details like rDNS, SPF, DKIM to ensure proper email authentication.
  • Improve Engagement: Focus on sending relevant, engaging content to users who actively want to receive it to improve engagement metrics.
  • Monitor Negative Signals: Actively monitor and address any negative signals such as user complaints and spam trap hits to minimize their impact on deliverability.
  • Stop & Re-Warm: If being blocked, stop sending for a few days, then re-warm your domain by gradually increasing sending volume, starting with your most engaged users.
  • Clean Sending Data: Regularly clean sending data to remove unengaged or inactive users to improve overall deliverability.
  • Avoid Sales Outreach: Ensure your sales team isn’t sending unsolicited outreach mail which can negatively impact your domain's reputation.
Expert view

Expert from Word to the Wise shares that Gmail's filtering algorithms are complex and consider a multitude of factors beyond just reputation, including user complaints and spam trap hits. A high reputation isn't a guarantee if other negative signals are present.

March 2023 - Word to the Wise
Expert view

Expert from Spam Resource explains that even with a high reputation in GPT, Gmail might block emails due to low engagement metrics. It's crucial to focus on sending engaging content to users who actively want it, to maintain a healthy sender reputation beyond technical configurations.

October 2021 - Spam Resource
Expert view

Expert from Email Geeks asks about the rDNS of the sending IP and whether the SPF/return path domain is the same as the DKIM domain. Additionally, Laura advises if you’re being blocked at Gmail: 1. Stop sending for 2 - 4 days. 2. Test it with your own addresses initially. If mail goes through, re-warm up your domain starting with the most engaged users. 3. Clean your sending data by looking at who is still a customer / engaged with your brand in other areas. 4. Make sure your sales team isn’t sending outreach mail.

January 2022 - Email Geeks

What the documentation says
4Technical articles

Gmail's filtering is based on multiple factors, including user engagement, spam complaints, and authentication, not just sender reputation. Incomplete or incorrect email authentication records (SPF, DKIM, DMARC) cause deliverability issues, even with a high IP reputation, since Gmail prioritizes authenticated senders. Shared IP addresses may cause deliverability issues, so poor practices from other senders on the same IP can affect everyone. A DMARC policy set to 'reject' can block legitimate emails if SPF/DKIM aren't aligned.

Key findings

  • Multifactorial Filtering: Gmail filtering uses user engagement, authentication, spam complaints, and more, beyond just sender reputation.
  • Authentication Priority: Gmail prioritizes properly authenticated senders, making SPF, DKIM, and DMARC records critical for deliverability.
  • Shared IP Risks: Shared IP addresses can negatively impact deliverability due to poor practices by other senders using the same IP.
  • DMARC Configuration: Incorrectly configured DMARC policies, especially a 'reject' policy without proper SPF/DKIM alignment, can block legitimate emails.

Key considerations

  • Optimize Engagement: Improve user engagement by sending relevant, desired content to recipients.
  • Implement Authentication: Ensure SPF, DKIM, and DMARC records are correctly implemented and aligned to properly authenticate emails.
  • Dedicated IP: Consider using a dedicated IP address to avoid negative impacts from other senders on a shared IP.
  • Review DMARC Settings: Carefully review DMARC settings to avoid inadvertently blocking legitimate emails and ensure alignment with SPF/DKIM.
Technical article

Documentation from DMARC.org describes that DMARC policy set to 'reject' can inadvertently block legitimate emails if SPF/DKIM are not properly aligned. Review DMARC settings for proper implementation.

July 2022 - DMARC.org
Technical article

Documentation from Google Support explains that Gmail's filtering systems consider numerous factors beyond sender reputation, including user engagement, authentication, and spam complaints. High reputation doesn't guarantee inbox placement.

April 2023 - Google Support
Technical article

Documentation from Microsoft explains that shared IP addresses might negatively impact deliverability even if the domain reputation is good. If other senders on the same IP have poor practices, it can affect everyone sharing that IP.

April 2023 - Microsoft Documentation
Technical article

Documentation from RFC-Editor explains that improper or missing email authentication records (SPF, DKIM, DMARC) can cause deliverability issues even with a high IP reputation, since Gmail prioritize authenticated senders.

January 2023 - RFC-Editor

Related resources
2Resources

Gmail Blocking Email? Find Out Why and How to Fix It
Gmail Blocking Email? Find Out Why and How to Fix It

Is Gmail blocking email you send to users with a @gmail or @googlemail address? Follow our troubleshooting guide to learn about Gmail email authentication.

SendLayer - Reliable Email Deliverability Made Easy
Why Gmail May be Blocking Your Emails | Mailgun
Why Gmail May be Blocking Your Emails | Mailgun

Emails blocked by Gmail may be due to various factors such as unapproved HTML or too many images. Learn how to get your campaigns through with Mailgun.

Mailgun

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