Summary
Gmail marks emails from new domains as spam primarily due to the absence of an established sender reputation. New domains lack a history that Gmail's filters can use to assess their legitimacy. Multiple factors contribute to this, including the IP address's prior reputation, the lack of proper email authentication (SPF, DKIM, DMARC), sending patterns, email content, and list hygiene. Warming up the domain gradually, maintaining a clean email list, monitoring feedback loops, personalizing emails, and addressing any sending infrastructure issues are crucial for improving deliverability. It's also important to acknowledge that Gmail's error messages can sometimes be misleading, and the filtering logic might have explainability issues.
Key findings
- Reputation Deficit: New domains lack an established sender reputation, making them prime targets for spam filters.
- Authentication is Key: Proper implementation of SPF, DKIM, and DMARC is essential for validating emails and preventing spoofing.
- Warming is Crucial: Gradually warming up a new domain and IP address is vital for building trust with ISPs like Gmail.
- Content Matters: Email content with spam trigger words or poorly coded HTML can trigger spam filters.
- Hygiene Counts: Maintaining a clean email list and removing unengaged subscribers can protect sender reputation.
- Patterns Signal: Inconsistent sending patterns can raise suspicion with Gmail; establishing a regular schedule helps.
- Infrastructure Impacts: Sending infrastructure issues, such as a shared IP with a poor reputation, can negatively affect deliverability.
- Error Message Inaccuracy: Gmail's error messages might not always accurately reflect the underlying reason for spam classification.
- Domain History: Domains can have a bad history even from the first email being sent.
Key considerations
- Age Awareness: Be aware that domain age affects deliverability; newer domains face more challenges.
- IP Scrutiny: Scrutinize the IP address associated with the domain; a previously used IP with a poor reputation can be detrimental.
- Engagement Focus: Prioritize engagement with recipients; positive engagement signals improve sender reputation.
- Authentication Setup: Ensure SPF, DKIM, and DMARC are correctly configured to authenticate emails.
- Content Review: Review email content for spam trigger words and clean HTML coding.
- Feedback Loop Monitoring: Monitor feedback loops to address spam complaints and improve deliverability.
- Personalization Strategy: Personalize email content to avoid being flagged as spam.
- Warming Schedule: Set up a domain/IP warming schedule, and do not send too much email too soon to your list.
What email marketers say
15 marketer opinions
Gmail marks emails from new domains as spam primarily due to the lack of established reputation. New domains have no history, making it difficult for Gmail's filters to determine their legitimacy. This can be compounded by factors such as the IP address's prior use by spammers, inconsistent sending patterns, and failure to implement proper email authentication protocols (SPF, DKIM, DMARC). Email content, list hygiene, and the presence of spam trigger words can also contribute. Warming up a new domain and IP address gradually, monitoring feedback loops, and maintaining good email practices are essential for improving deliverability.
Key opinions
- Reputation: New domains lack an established sender reputation, which is a critical factor in Gmail's spam filtering.
- Authentication: Failure to properly implement SPF, DKIM, and DMARC authentication increases the likelihood of emails being marked as spam.
- Warming Up: Gradually increasing sending volume from a new domain and IP address is crucial for establishing trust with Gmail.
- Content: Using spam trigger words and poor HTML coding can trigger spam filters.
- List Hygiene: Sending emails to unengaged or invalid addresses damages sender reputation and increases the risk of spam classification.
- Sending Patterns: Inconsistent sending patterns raise red flags with Gmail. Establishing a regular schedule is recommended.
- Feedback Loops: Monitoring feedback loops provides valuable data about spam complaints and helps address deliverability issues.
- Personalization: Generic, non-personalized email content, especially when sent in bulk, can easily be identified as spam by Gmail.
Key considerations
- Domain Age: Consider the age of the domain. Older, established domains are less likely to be flagged as spam.
- IP Reputation: Check the IP address's reputation. A previously used IP address with a poor reputation can negatively impact deliverability.
- Email Preview: Preview emails across different email clients to ensure proper rendering and avoid triggering spam filters due to faulty code.
- Engagement: Focus on building engagement with email recipients. Positive engagement signals (opens, clicks, replies) improve sender reputation.
- Correct Explanation: It's important to consider the explanation Gmail provides for marking an email as spam, while recognizing that the explanation itself can be flawed.
Marketer view
Email marketer from Email Geeks suggests the domain might have been previously used by a spammer, which could explain the spam classification.
29 Aug 2022 - Email Geeks
Marketer view
Email marketer from GlockApps explains that setting up feedback loops can help monitor and improve sender reputation with Gmail. Feedback loops provide data about spam complaints, enabling you to address issues proactively.
15 Mar 2023 - GlockApps
What the experts say
4 expert opinions
Gmail marks emails from new domains as spam primarily due to a lack of established reputation. This lack of reputation makes it difficult for Gmail's filtering algorithms to accurately assess the legitimacy of the emails, resulting in aggressive filtering. Issues with sending infrastructure, such as shared IPs or the use of cold-calling tools, can also contribute to spam classification. While Gmail's error messages can sometimes be inaccurate, the underlying issue is often related to the absence of a positive domain reputation.
Key opinions
- Reputation: New domains lack an established reputation, making them suspect to Gmail's spam filters.
- Sending Infrastructure: Issues with the sending infrastructure, like shared IPs or cold-calling tools, can negatively impact deliverability.
- Filtering Algorithm: Gmail's filtering algorithms have no basis to determine email acceptance when using a new domain.
Key considerations
- Domain Reputation: Building a positive domain reputation is crucial for improving deliverability to Gmail.
- Infrastructure Review: Carefully review the sending infrastructure to ensure it is not contributing to spam classification.
- Message Accuracy: While humorous, inaccurate error messages may mask the underlying issue of poor domain reputation.
Expert view
Expert from Email Geeks suggests the issue might be related to the sending infrastructure, such as a shared IP, or use of a cold-calling email tool.
7 Mar 2025 - Email Geeks
Expert view
Expert from Email Geeks highlights the humour in Gmail's wildly wrong error message.
26 Sep 2021 - Email Geeks
What the documentation says
4 technical articles
Gmail's spam filters mark emails from new domains as spam because these domains lack an established sender reputation. Gmail considers sender reputation, authentication (SPF, DKIM, DMARC), and user engagement to determine if an email is spam. New domains lack history in these areas, increasing the risk of filtering. Implementing SPF and DMARC is crucial for authenticating emails and preventing spoofing, which helps establish legitimacy with Gmail and other email platforms. Low domain or IP reputation can hinder deliverability.
Key findings
- Reputation: New domains lack an established sender reputation, which is a key factor in Gmail's spam filtering process.
- Authentication: Proper email authentication (SPF, DKIM, DMARC) is critical for establishing legitimacy and preventing spoofing.
- Factors: Gmail's spam filters consider sender reputation, authentication, and user engagement.
- Domain Reputation Impacts Platforms: Poor domain or IP reputation can affect deliverability on multiple email platforms, including Gmail and Microsoft.
Key considerations
- SPF Implementation: Implement SPF records to specify which mail servers are authorized to send emails on behalf of the domain.
- DMARC Configuration: Set up DMARC to monitor and control email authentication, preventing malicious use of the new domain and ensuring alignment with SPF and DKIM.
- Sender Reputation Efforts: Actively work to build a positive sender reputation by following email best practices and engaging with recipients.
Technical article
Documentation from DMARC.org details the importance of DMARC implementation to monitor and control email authentication, preventing malicious use of a new domain. It advises ensuring alignment and reports are monitored.
17 Sep 2023 - DMARC.org
Technical article
Documentation from Google Support explains that Gmail's spam filters consider various factors, including sender reputation, authentication, and user engagement, to determine whether an email is spam. New domains lack established reputation, increasing the risk of filtering.
26 Aug 2021 - Google Support
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