How can I fix consistent spam landing in Gmail with 0% user-reported spam when using Mailchimp?
Matthew Whittaker
Co-founder & CTO, Suped
Published 5 Jul 2025
Updated 17 Aug 2025
6 min read
Landing in Gmail's spam folder, especially when you have 0% user-reported spam, can be incredibly frustrating. This issue is particularly perplexing when using a reputable email service provider like Mailchimp, where IPs are generally clean. While a clean IP and no direct spam complaints are good indicators, Gmail's filtering system is complex and considers many other factors beyond explicit user reports.
We often see situations where a root domain has a high reputation in Google Postmaster Tools, but a newer subdomain used for Mailchimp campaigns dips to medium or low reputation. This indicates that Gmail is identifying patterns in your Mailchimp-sent emails that trigger its spam filters, even without direct user complaints.
The core message from Gmail, "Why is this message in spam? It is similar to messages that were identified as spam in the past," is a critical clue. It suggests that your historical sending patterns or content characteristics are causing the problem, not necessarily a new issue or direct subscriber feedback. To fix this, a multi-faceted approach focusing on technical setup, content, and audience engagement is essential.
Strengthening your email authentication
While your root domain may have a good standing with Google, subdomains typically build their own separate sending reputations. If a new subdomain used with Mailchimp starts with a low or medium reputation in Google Postmaster Tools, it directly impacts your inbox placement.
Mailchimp provides tools to help you verify your domain, which is crucial for authenticating your emails. This involves correctly setting up SPF and DKIM records that align with your sending domain. Even if Mailchimp manages the IP, your domain's authentication is paramount.
Another critical component is DMARC. A properly configured DMARC record ensures that your SPF and DKIM authentication align with your 'From' address domain, a key requirement for modern email providers like Gmail. Without strong DMARC, emails are more likely to be flagged as suspicious, even without explicit spam complaints.
The message about emails being "similar to messages that were identified as spam in the past" indicates a content issue that needs immediate attention. This isn't just about avoiding obvious spam trigger words, but about the overall message structure, image-to-text ratio, and the types of links included.
Review your email content for anything that might appear generic or overly promotional. Personalized content, relevant offers, and clear calls to action generally perform better. If you use many images, try balancing them with more text. Consider running A/B tests on different subject lines and content variations to see what resonates with your audience and avoids spam folders.
Mailchimp's segmentation features are powerful tools here. Start by sending to your most engaged subscribers first. These are the people who consistently open your emails and click your links. Positive engagement signals from this highly active segment can help improve your sending reputation with Gmail over time. Slowly expand to less engaged segments as your deliverability improves. This is a crucial step in fixing Gmail deliverability issues.
Regularly clean your email lists. Remove inactive subscribers, hard bounces, and any addresses that haven't engaged with your emails in a long time. Sending to a clean, engaged list signals to Gmail that your emails are valued by recipients, which positively impacts your sender reputation.
Content and engagement best practices
Personalization: Tailor your emails to individual subscriber interests and behaviors.
Clear subject lines: Avoid deceptive or overly salesy language that could trigger spam filters.
Valuable content: Provide information or offers that genuinely benefit your audience.
Engagement strategy: Encourage replies, stars, or moving emails to the inbox.
Re-warming your sending reputation
Even if your Mailchimp IPs are clean, your subdomain's reputation with Gmail might be damaged. Re-warming a domain or subdomain after deliverability issues requires a strategic approach. It's not about taking a complete break, but rather sending small volumes of highly engaging emails to your most active subscribers.
Consider sending a whitelisting campaign from a reliable sending method (perhaps not directly through the problematic Mailchimp subdomain initially, if possible). This campaign would ask subscribers to add your "From" address to their contacts. For those who open this email, follow up with a campaign from your Mailchimp subdomain, continuing to build positive engagement signals.
Continuously monitor your deliverability using Mailchimp's reports and Gmail Postmaster Tools. Pay close attention to any delivery errors or flags, even if they aren't explicit spam complaints. Look at your bounce rates and SMTP replies for clues. This proactive monitoring is key to identifying and addressing issues before they escalate.
Current state: Gmail spam folder
Emails consistently land in Gmail spam, despite 0% user-reported spam and clean Mailchimp IPs. Google Postmaster Tools (Mailchimp help) for the subdomain shows low reputation. Gmail indicates messages are "similar to spam in the past."
Reputation issues
Subdomain reputation is low, affecting all sends through Mailchimp, even plain text emails. This indicates a content or engagement problem, not just technical deliverability.
Goal: Inbox placement
Emails consistently reach the Gmail inbox. Subdomain reputation in Google Postmaster Tools is high.
Strategic improvements
Focus on highly engaged segments, vary content to avoid historical spam patterns, ensure DKIM alignment (Mailchimp DKIM domain is the same as yours), and implement DMARC.
Understanding the silent spam placement
When your emails consistently land in spam, even with a 0% user-reported spam rate, it points to deeper issues beyond overt complaints. It's often about how mailbox providers, like Gmail, perceive your sending behavior and content characteristics over time. The lack of user complaints means recipients aren't actively flagging your emails, but Gmail's algorithms are still categorizing them as spam.
This usually indicates a subtle but pervasive problem with your sender reputation, often tied to low engagement, inconsistent sending practices, or content that triggers internal spam filters. It's a signal that Gmail trusts your domain less for the specific type of mail you're sending from Mailchimp.
Addressing this requires a comprehensive review of your email program, including authentication, list hygiene, content strategy, and a gradual re-engagement approach with your audience. Remember, inbox placement is not just about avoiding blacklists, but about building and maintaining a positive sending relationship with mailbox providers.
Views from the trenches
Best practices
Always align your Mailchimp DKIM domain with your sender's 'From' domain for optimal authentication.
Segment your audience aggressively and prioritize sending to your most engaged subscribers first to build positive signals.
Regularly clean your email lists to remove inactive or unengaged recipients, improving overall list health.
Vary your email content, subject lines, and calls to action to avoid patterns that Gmail might associate with spam.
Continuously monitor your domain's reputation using Google Postmaster Tools, particularly for subdomains.
Common pitfalls
Assuming 0% user-reported spam means perfect deliverability; Gmail's internal filters use many other signals.
Neglecting subdomain reputation; each subdomain has its own standing with mailbox providers.
Sending the same type of content repeatedly, leading Gmail to classify it as 'similar to past spam'.
Not implementing DMARC or having an enforcement policy that is too lax.
Ignoring engagement metrics beyond opens, such as clicks, replies, or emails moved from spam.
Expert tips
For Mailchimp users, ensure your domain is properly authenticated via DKIM and SPF to ensure Mailchimp sends on your behalf.
When recovering reputation, start with small sends to highly engaged segments and gradually increase volume.
Use email headers and Google Postmaster Tools for specific clues on why emails are going to spam.
A "whitelisting campaign" can help by asking engaged users to add you to their contacts, improving trust signals.
Remember that even plain text emails can land in spam if the domain's reputation or content patterns are problematic.
Expert view
Expert from Email Geeks says that understanding the specific mailbox provider, like Google, is crucial. Examining breadcrumbs in email headers or using Google Postmaster Tools (GPT) can reveal the root cause of inbox placement issues.
May 17, 2024 - Email Geeks
Expert view
Expert from Email Geeks says that if Gmail reports messages are similar to past spam, the sender needs to change their tactics, segmentation, messaging, and review their acquisition practices to avoid historical patterns.
May 17, 2024 - Email Geeks
Key takeaways for reliable deliverability
Resolving consistent Gmail spam placement when using Mailchimp, especially with 0% user-reported spam, hinges on a proactive and multi-layered strategy. It's not just about avoiding direct complaints; it's about optimizing your sender reputation through proper authentication, smart content creation, and meticulous audience engagement.
By reinforcing your SPF, DKIM, and DMARC records, refining your content to be less 'spam-like,' and leveraging Mailchimp's segmentation to target your most engaged subscribers, you can gradually rebuild your subdomain's reputation with Gmail. Consistency in these practices and continuous monitoring through Google Postmaster Tools will be key to long-term inbox success.
