Summary
Gmail flags messages as suspicious due to low sender reputation based on numerous factors. These factors include a history of sending spam or unwanted emails, email practices that don't meet Gmail's standards (e.g., unsolicited emails, high complaint rates, lack of authentication), newness of the sending domain/IP, high bounce rates, low user engagement (opens, clicks, replies), inconsistent sending volumes, recipients marking emails as spam, and broader contextual reputations. Experts emphasize the importance of good list hygiene, consistent sending patterns with valuable content, proper authentication, and actively managing sender behavior to build and maintain a positive reputation, ultimately improving deliverability.
Key findings
- Multi-Factor Reputation: Sender reputation is influenced by numerous factors, encompassing sending history, engagement, infrastructure, and content.
- History Matters: A history of sending spam or unwanted emails significantly lowers sender reputation.
- Engagement is Key: Low user engagement (low open rates, clicks, and replies) contributes to a poor sender reputation.
- Infrastructure Affects Reputation: The age and authentication status of your domain and IP address impact sender reputation.
- Complaints are Detrimental: High spam complaint rates from recipients negatively affect sender reputation.
- List Hygiene is Critical: High bounce rates resulting from poor list hygiene damage sender reputation.
- Contextual Factors: Broader external events or affiliations can influence Gmail's perception of a sender.
Key considerations
- Monitor Reputation: Actively monitor sender reputation to identify and address issues promptly.
- Practice List Hygiene: Regularly clean and update email lists to minimize bounce rates and spam complaints.
- Authenticate Emails: Implement proper email authentication protocols (SPF, DKIM, DMARC) to verify sender identity.
- Improve Engagement: Focus on creating valuable and engaging content to encourage user interaction.
- Manage Sending Volume: Gradually increase email sending volumes to avoid triggering spam filters.
- Solicit Positive Feedback: Encourage recipients to mark legitimate emails as 'not spam' to improve sender reputation.
- Address Past Issues: Address any past spam-related issues to rebuild trust with Gmail.
- New Infrastructure Warm Up: Warm up new domains and IP addresses slowly and consistently before sending bulk emails.
What email marketers say
8 marketer opinions
Gmail flags messages as suspicious due to low sender reputation when the sending IP address or domain has a history of sending spam, unwanted emails, or email practices that don't meet Gmail's standards. Several factors contribute to this low reputation, including sending unsolicited emails, high spam complaint rates, lack of proper authentication, a relatively new domain or IP address, high bounce rates, low user engagement (opens, clicks, replies), inconsistent sending volumes, and recipients marking emails as spam. Building a positive reputation involves consistent and legitimate email sending practices, maintaining a clean email list, encouraging engagement, and gradually increasing sending volumes.
Key opinions
- Spam History: A history of sending spam or unwanted emails from your IP address or domain will result in a low sender reputation.
- Poor Email Practices: Sending unsolicited emails, having high spam complaint rates, and lacking proper authentication contributes to a negative sender reputation.
- New Domain/IP: Relatively new domains or IP addresses may have a lower sender reputation until a positive track record is established.
- High Bounce Rate: A high bounce rate negatively impacts sender reputation, signaling poor list hygiene.
- Low Engagement: Low open rates, click-through rates, and replies indicate that your emails may be unwanted, lowering sender reputation.
- Inconsistent Volume: Inconsistent sending volumes or sudden spikes can trigger suspicion and negatively affect your reputation.
- Spam Complaints: A high percentage of recipients marking emails as spam severely damages sender reputation.
Key considerations
- Consistent Practices: Adopt consistent and legitimate email sending practices to build a positive reputation over time.
- List Hygiene: Maintain a clean and up-to-date email list to reduce bounce rates and spam complaints.
- Engagement: Encourage user engagement with your emails through valuable content and clear calls to action.
- Volume Ramp-Up: Gradually increase sending volumes to avoid triggering spam filters and maintain a stable sending reputation.
- Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) to verify your identity and improve deliverability.
- Spam Feedback: Encourage recipients to mark your emails as 'not spam' if they accidentally end up in the spam folder to improve your reputation.
Marketer view
Email marketer from Reddit shares that Gmail often flags emails as suspicious if your domain is new and lacks history. Build a consistent sending pattern with valuable content to improve your reputation over time.
27 Aug 2023 - Reddit
Marketer view
Email marketer from SendPulse shares that Gmail flags messages as suspicious due to a low sender reputation when the sender's email practices don't meet Gmail's standards. This includes issues such as sending unsolicited emails, having a high spam complaint rate, or lacking proper authentication.
31 Jan 2023 - SendPulse
What the experts say
3 expert opinions
Gmail flags messages as suspicious due to low sender reputation, influenced by factors like sender behavior, broader contextual reputations (such as recent events or bans), complaint rates, engagement metrics, authentication practices, and list hygiene. Experts suggest that poor performance in these areas makes messages more likely to be flagged, highlighting the importance of addressing these factors to improve deliverability.
Key opinions
- Sender Behavior: Sender behavior and mailing list practices significantly influence sender reputation.
- Broader Reputations: External events and broader contextual reputations can affect how Gmail perceives senders.
- Complaint Rates: High complaint rates negatively impact sender reputation, leading to messages being flagged.
- Engagement Metrics: Poor engagement metrics (low opens, clicks) indicate a lack of interest and can harm sender reputation.
- Authentication: Lack of proper email authentication practices contribute to a low sender reputation.
- List Hygiene: Poor email list hygiene practices (e.g., sending to invalid addresses) contribute to a low sender reputation.
Key considerations
- Monitor Sending Practices: Regularly monitor and optimize sending practices to avoid triggering spam filters.
- Address Broader Context: Be aware of how external events could influence perceived sender reputation.
- Reduce Complaint Rates: Implement strategies to reduce complaint rates, such as sending relevant content and making unsubscribing easy.
- Improve Engagement: Focus on improving engagement metrics by creating compelling content and segmenting audiences effectively.
- Implement Authentication: Properly authenticate your emails to verify your identity and improve deliverability.
- Maintain Clean List: Regularly clean your email list to remove invalid or inactive addresses.
Expert view
Expert from Email Geeks responds to a question about Gmail flagging messages as suspicious due to low sender reputation. Laura suggests that the issue might be related to broader reputations, especially considering recent events. She believes the senders' behavior is likely the cause, especially after certain bans.
22 Dec 2021 - Email Geeks
Expert view
Expert from Word to the Wise shares that a low sender reputation can result in Gmail flagging messages due to factors such as poor list hygiene practices, high spam complaint rates, and a lack of engagement from recipients. Improving these areas is key to better deliverability.
1 Aug 2024 - Word to the Wise
What the documentation says
3 technical articles
Gmail's filtering process relies heavily on sender reputation, which is influenced by the sending domain and IP address's behavior over time. Factors determining reputation include email volume, spam complaints, and engagement metrics. A low sender reputation increases the likelihood of messages being filtered to spam or blocked, while a good reputation improves the chances of reaching the inbox.
Key findings
- Reputation Importance: Sender reputation is a key factor in Gmail's filtering process.
- Domain Impact: Domain behavior, including email volume, spam complaints, and engagement metrics, determines domain reputation.
- IP Address Impact: The sending habits of the IP address, including email volume, spam complaints, and engagement metrics, determine IP address reputation.
- Deliverability Consequence: Low sender reputation increases the likelihood of messages being filtered to spam or blocked.
- Inbox Consequence: Good sender reputation improves the chances of messages reaching the inbox.
Key considerations
- Monitor Sending Habits: Monitor sending habits to ensure compliance with best practices and maintain a positive reputation.
- Manage Email Volume: Manage email volume to avoid triggering spam filters.
- Minimize Spam Complaints: Minimize spam complaints by sending relevant and engaging content.
- Improve Engagement: Improve engagement metrics through targeted campaigns and valuable content.
- Domain & IP: Understand that both your domain and IP address reputations impact deliverability.
Technical article
Documentation from Microsoft responds that IP address reputation is determined by the sending habits of the IP address over time, including email volume, spam complaints, and engagement metrics. IP address reputation is a critical factor in Gmail's filtering process.
14 Jan 2024 - Microsoft
Technical article
Documentation from Google Support explains that sender reputation is a key factor in Gmail's filtering process. Senders with a low reputation are more likely to have their messages filtered to spam or blocked entirely, while senders with a good reputation are more likely to reach the inbox.
22 Aug 2023 - Google Support
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