Why are my emails going to spam in Gmail even though everything seems technically correct?

Summary

Despite having a technically correct email setup (SPF, DKIM, DMARC), emails can still land in Gmail spam folders due to various interconnected factors that influence sender reputation and engagement. These include content quality resembling spam, image hosting practices, compliance with RFC 8058 for one-click unsubscribe, the use of multiple ESPs in a suspicious manner, sender reputation (including IP warming, shared IPs, and spam complaints), list hygiene, user engagement (opens and clicks), and the complex, ever-evolving algorithms used by mailbox providers. Proactive monitoring, continuous optimization, and adaptation to evolving best practices are critical for maintaining high deliverability.

Key findings

  • Holistic Spam Evaluation: Gmail’s spam filters consider many signals beyond technical configurations, including content, sender reputation, and user engagement.
  • Content is King: Email content resembling spam, using spam trigger words, or having misleading subject lines negatively impacts deliverability.
  • Sender Reputation's Impact: Sender reputation, influenced by IP warming, shared IPs, spam complaints, and domain age, is a major factor in deliverability.
  • Engagement Matters: Low engagement rates signal to Gmail that emails are unwanted.
  • List Hygiene is Critical: Maintaining a clean email list and minimizing spam complaints are essential for a good sending reputation.
  • Algorithms Evolve: Mailbox providers constantly update spam filtering algorithms, necessitating continuous monitoring and adaptation.
  • Compliance Requirements: Adherence to email standards like RFC 8058 one-click unsubscribe is critical.

Key considerations

  • Optimize Content: Refine email content to avoid spam triggers, and focus on providing value to recipients.
  • Manage Reputation: Implement IP warming strategies for new domains/IPs and monitor sender reputation metrics.
  • Engage Subscribers: Send relevant content, segment your audience, and prune inactive subscribers.
  • Implement RFC 8058: Implement RFC 8058 one-click unsubscribe to improve deliverability.
  • Analyze Sending Practices: Review image hosting configurations and avoid suspicious use of multiple ESPs.
  • Continuous Monitoring: Monitor deliverability metrics and adapt strategies based on performance and algorithm changes.
  • Authentication Check: Ensure correct set up of SPF, DKIM and DMARC protocols.

What email marketers say
11Marketer opinions

Even with technically correct email setups (SPF, DKIM, DMARC), emails can still land in Gmail spam folders due to a variety of factors. These include sender reputation (influenced by IP warming, shared IPs, spam complaints), content triggers (spam words, capitalization), lack of RFC 8058 one-click unsubscribe, poor engagement rates, image hosting issues, and email list hygiene. Continuous monitoring, optimization, and adaptation to Gmail's algorithm changes are essential.

Key opinions

  • Authentication: Proper setup of SPF, DKIM, and DMARC is essential but not always sufficient. Monitor regularly.
  • Sender Reputation: Sender reputation is critical. New domains/IPs require warming. Shared IPs can negatively impact deliverability.
  • Content Matters: Content triggers, misleading subject lines, and excessive capitalization can cause spam filtering.
  • Engagement is Key: Low engagement (opens/clicks) signals unwanted email to Gmail.
  • List Hygiene: Maintaining a clean email list and minimizing spam complaints are critical for a good sending reputation.

Key considerations

  • RFC 8058: Ensure compliance with RFC 8058 one-click unsubscribe to avoid deliverability issues.
  • Image Hosting: Consolidate image hosting and avoid using multiple domains to reduce suspicion.
  • Feedback Loops: Enroll in feedback loops (FBLs) to manage spam complaints effectively.
  • A/B Testing: Continuously A/B test subject lines, sender names, and content to optimize engagement.
  • Monitor Metrics: Regularly monitor key metrics (spam complaints, engagement) and adapt your strategy based on performance.
Marketer view

Email marketer from GMass shares that low engagement rates (opens, clicks) can signal to Gmail that your emails are unwanted. Focus on sending relevant content to engaged subscribers and pruning inactive users from your list to improve deliverability.

March 2023 - GMass
Marketer view

Email marketer from Reddit shares that even if everything seems technically correct, the sender's reputation plays a crucial role. If your domain or IP address is new or has a history of sending spam, Gmail will likely filter your emails. Warming up your IP and domain gradually is vital.

December 2023 - Reddit
Marketer view

Email marketer from Constant Contact responds that maintaining a clean email list is crucial for deliverability. Regularly remove inactive subscribers, bounce addresses, and users who have unsubscribed to reduce spam complaints and improve your sender reputation.

January 2023 - Constant Contact
Marketer view

Email marketer from Woodpecker explains that A/B testing subject lines, sender names, and email content can help you identify what resonates with your audience and avoid spam filters. Continuously optimize your emails based on performance data.

April 2021 - Woodpecker.co
Marketer view

Email marketer from Email Geeks agrees with Steve on the image hosting and links using multiple domains and advises aligning these with the sending domain.

July 2024 - Email Geeks
Marketer view

Email marketer from Email Geeks questions the 'from' name mi.ua, asking if it's a brand name.

November 2022 - Email Geeks
Marketer view

Email marketer from Neil Patel explains that even if your email setup seems technically correct, Gmail might still mark your emails as spam due to issues with authentication (SPF, DKIM, DMARC) and sender reputation. Ensure these are properly configured and monitored.

June 2021 - Neil Patel
Marketer view

Email marketer from Email Marketing Forum responds that high spam complaint rates can negatively impact deliverability. Enrolling in feedback loops (FBLs) allows you to identify and remove subscribers who mark your emails as spam, which can improve your sender reputation.

October 2023 - Email Marketing Forum
Marketer view

Email marketer from Email Geeks shares that as of June 1, 2024, Google requires that email headers support RFC 8058 one-click list-unsubscribe. If you don't comply, Gmail will not deliver your emails

March 2022 - Email Geeks
Marketer view

Email marketer from Mailjet responds that a poor IP address reputation can lead to emails being marked as spam. If you're using a shared IP, the actions of other senders can affect your deliverability. Consider using a dedicated IP address to control your reputation.

May 2023 - Mailjet
Marketer view

Email marketer from Sendinblue shares that content can be a significant factor in triggering spam filters. Using spam trigger words, excessive capitalization, or misleading subject lines can cause emails to land in spam. Review your email content to avoid these triggers.

August 2024 - Sendinblue

What the experts say
8Expert opinions

Even with technically correct email setups, emails can still land in Gmail spam folders due to complex and evolving filtering algorithms. Factors contributing to this include content resembling spam, issues with shared image hosting domains, non-compliance with RFC8058 one-click unsubscribe, suspicious use of multiple ESPs, and the quality/relevance of email content. Continuous monitoring of metrics and adaptation to algorithm changes by mailbox providers is essential.

Key opinions

  • Content Analysis: Gmail analyzes email content, and similarities to known spam can trigger filtering.
  • Image Hosting: Using shared image hosting domains or a mix of different hosting providers can negatively impact deliverability.
  • RFC 8058 Compliance: Lack of RFC8058 one-click unsubscribe can lead to emails being marked as spam, especially for new senders.
  • Multiple ESP Usage: Using links from campaigns sent via one ESP while mailing through another can appear suspicious.
  • Algorithm Evolution: Mailbox providers constantly update spam filtering algorithms, requiring ongoing adaptation.

Key considerations

  • Content Optimization: Ensure email content is high quality and relevant to recipients to avoid spam triggers.
  • Image Hosting Review: Review and potentially consolidate image hosting to avoid issues with shared or untrusted domains.
  • Implement RFC 8058: Prioritize implementing RFC 8058 one-click unsubscribe for improved deliverability.
  • ESP Consistency: Maintain consistency in sending practices across different ESPs to avoid suspicious behavior.
  • Continuous Monitoring: Continuously monitor deliverability metrics and adapt your strategies to address algorithm changes.
Expert view

Expert from Email Geeks suggests that missing 8058 could be an immediate problem, especially without a history of sending wanted email, even if existing mail is being sent successfully elsewhere without it.

January 2025 - Email Geeks
Expert view

Expert from Word to the Wise answers that Gmail's spam filtering algorithms are complex and consider numerous factors beyond technical configurations. Content quality, relevance to the recipient, and engagement metrics (opens, clicks, replies) all play a significant role. Even seemingly minor issues can trigger spam filters.

June 2024 - Word to the Wise
Expert view

Expert from Email Geeks explains that using links from a campaign sent by one ESP (e.g., Bloomreach) while mailing through another ESP (e.g., Selzy) would look suspicious and could trigger spam filters.

April 2021 - Email Geeks
Expert view

Expert from Email Geeks explains that if the customer's email is landing in the spam folder on Gmail, the reason "similar to messages identified as spam" means that the content looks like unwanted email to Google.

October 2023 - Email Geeks
Expert view

Expert from Email Geeks notes that not having RFC8058 one-click unsubscribe won't help avoid spam filters.

December 2024 - Email Geeks
Expert view

Expert from Email Geeks points out the mix of image hosting on cloudfront, i.mi.us, brxcdn.com and cdn.exponea.com and suggests to check if this intentional.

December 2024 - Email Geeks
Expert view

Expert from Email Geeks shares that using cdn.exponea.com to host images could be a problem because it's a shared domain.

June 2024 - Email Geeks
Expert view

Expert from SpamResource explains that mailbox providers are constantly updating their algorithms to identify spam, so even if you've implemented best practices, changes in these algorithms can affect your deliverability. Monitor your metrics and adjust your strategies as needed.

January 2023 - SpamResource

What the documentation says
6Technical articles

Even with technically correct setups, emails can still land in spam due to various signals assessed by email providers. These signals include user reports, content analysis, sender reputation, and the absence of essential features like List-Unsubscribe headers. Maintaining a positive reputation requires IP/domain warming, proper DMARC implementation, and ongoing monitoring of authentication reports to prevent spoofing and unauthorized use.

Key findings

  • Multifaceted Spam Filtering: Gmail and Outlook use diverse signals beyond technical setup to identify spam, including user reports and content analysis.
  • User Feedback: Negative user feedback significantly impacts deliverability.
  • List-Unsubscribe Header: The presence of a List-Unsubscribe header improves sender reputation and deliverability.
  • Importance of DMARC: Implementing and monitoring DMARC is essential for preventing unauthorized use of your domain and improving deliverability.
  • IP/Domain Warming: Warming up IP addresses and domains gradually is crucial for establishing a positive sending reputation, especially for new setups.
  • DKIM Authentication: Using DKIM signatures authenticates your emails and prevents spoofing.

Key considerations

  • Monitor User Feedback: Actively monitor user feedback and address any negative trends promptly.
  • Implement DMARC: Implement a DMARC policy and regularly monitor DMARC reports.
  • List Hygiene: Maintain a clean and engaged email list.
  • Gradual IP Warming: Follow a gradual IP warming process for new IP addresses and domains.
  • Proper DKIM Setup: Ensure proper DKIM signature implementation to authenticate your emails.
Technical article

Documentation from DKIM.org details that using DKIM signatures to authenticate emails is essential to prove that the message was sent and authorized by the owner of the domain. This helps prevent spoofing and improves deliverability.

February 2024 - DKIM.org
Technical article

Documentation from SparkPost details how warming up your IP address and domain gradually by increasing sending volume over time to establish a positive sending reputation. This is especially important for new IP addresses and domains.

July 2023 - SparkPost
Technical article

Documentation from Microsoft support explains that Outlook and other email clients use various factors to determine if an email is junk, including the sender's reputation, the content of the email, and user feedback. If many users mark your emails as junk, your emails are more likely to be filtered.

March 2023 - Microsoft Support
Technical article

Documentation from DMARC.org explains that implementing a DMARC policy and monitoring DMARC reports can help you identify and address unauthorized use of your domain, which can protect your sender reputation and improve deliverability. Review your DMARC reports regularly to detect and prevent spoofing attacks.

October 2024 - DMARC.org
Technical article

Documentation from RFC 2369 details about the importance of including a List-Unsubscribe header in your emails as this allows users to easily unsubscribe, which can improve your sender reputation.

October 2022 - RFC 2369
Technical article

Documentation from Google Workspace Admin Help explains that Gmail's spam filters consider a variety of signals, including user reports, content analysis, and sender reputation. Even with proper technical setup, negative signals can cause emails to be filtered as spam.

May 2024 - Google Workspace Admin Help