Are regular emails frequently going to spam in Gmail and G Suite?
Michael Ko
Co-founder & CEO, Suped
Published 21 Jul 2025
Updated 21 Jul 2025
5 min read
Summary
Occasionally, users of Gmail and G Suite may observe an unexpected increase in the number of legitimate emails being directed to their spam folders. While Gmail's spam filters are highly advanced and typically effective at identifying unwanted messages, even regular correspondence can sometimes be miscategorized. This phenomenon, though often anecdotal, can signal underlying issues with sender reputation, email authentication, or content filtering.
Key findings
Anecdotal evidence: Some users report that even long-standing, regular email correspondence with known contacts suddenly lands in spam.
System glitches: While rare, temporary glitches in Gmail's spam detection algorithms can lead to legitimate emails being misclassified.
Authentication status: Even if emails pass SPF, DKIM, and DMARC checks, other factors can still trigger spam filters.
User interaction: Gmail's filtering relies heavily on user engagement. A sudden change in this pattern, even for personal emails, can be flagged.
Key considerations
Monitor consistently: Observe if such spam placement becomes a consistent pattern rather than isolated incidents. A sustained issue requires deeper investigation into your sender reputation.
Check email headers: Always analyze the full email headers of misdirected messages to understand Gmail's specific reasons for spam categorization. This provides critical clues about which filter tripped.
Review bulk sender guidelines: Even for regular sending, ensure compliance with Google's updated sender requirements, particularly concerning authentication and spam rates.
Address potential blocklists: Check if your sending IP or domain has inadvertently landed on any email blocklists or blacklists, as this significantly impacts deliverability to Gmail and other providers.
What email marketers say
Email marketers often face the challenge of ensuring their messages land in the inbox, especially with sophisticated filters like Gmail’s. When even regular, expected emails start hitting the spam folder, it raises immediate concerns about changes in filtering behavior or underlying deliverability issues that might not be immediately obvious. This can be particularly frustrating for personal or transactional emails that are crucial for user experience and business operations.
Key opinions
Unusual occurrences: Many marketers note that it's uncommon for frequently exchanged, legitimate emails to be marked as spam, suggesting a potential shift in Gmail's filtering logic.
Consistency matters: If email authentication (SPF, DKIM, DMARC) is in place, and the sending practices haven't changed, a sudden drop in inbox placement might point to external factors or an adjustment in Google's algorithms.
User behavior impact: Even for personal accounts, user interaction history heavily influences Gmail's spam decisions. A lack of engagement or accidental spam reports can impact future deliveries.
Domain reputation fluctuations: A general decline in domain reputation can affect even one-to-one communications, as all email from a domain is subject to its overall standing.
Key considerations
Analyze headers thoroughly: Always inspect the original email headers when emails go to spam. These provide crucial diagnostic information from Gmail regarding its filtering decisions.
Review authentication: Double-check your SPF, DKIM, and DMARC records to ensure they are correctly configured and aligned, especially if you've recently made changes to your sending infrastructure.
Check content: Even in regular emails, certain content patterns, excessive links, or suspicious phrasing could trigger spam filters. While less common for personal emails, it's a factor.
Monitor spam rates: Keep a close eye on your spam rate in Google Postmaster Tools. This is a primary indicator of your sending health, and a sudden spike can affect deliverability across the board.
Look for patterns: If the issue becomes a pattern, it signals a deeper problem beyond a one-off glitch. This would require a more comprehensive review of your overall email deliverability strategy, as outlined by deliverability guides.
Marketer view
Email marketer from Email Geeks observes unusual spam placement in Gmail and G Suite. They noticed personal correspondence with friends, with whom they frequently communicate, suddenly going to the spam folder. This behavior seems odd, given Gmail's usual ability to learn and recognize established legitimate mail. They are curious if others have experienced this issue at a similar or larger scale recently. Despite the emails being authenticated, this suggests a potential glitch or temporary shift in Google’s filtering.
03 Oct 2019 - Email Geeks
Marketer view
Marketer from Quora suggests that when emails go to spam, the sending domain might be known or suspected of sending spam, even if the current message is legitimate. This can be a major factor in how Gmail filters incoming mail, regardless of the individual sender's reputation. Additionally, specific words or patterns within the email content can also trigger spam filters. These content-based triggers are often less obvious than domain reputation issues but can still lead to undesirable spam placement.
10 Mar 2023 - Quora
What the experts say
Deliverability experts continually monitor and analyze the intricate algorithms used by mailbox providers like Gmail to filter emails. They understand that while authentication is fundamental, it's merely one piece of a much larger puzzle. Factors such as sender reputation, engagement metrics, and even subtle changes in email content or sending patterns can significantly influence inbox placement.
Key opinions
Holistic view: Experts emphasize that Gmail's filtering is based on hundreds of signals, not just a few. A sudden increase in spam placement often points to a combination of factors rather than a single smoking gun.
Reputation is key: Sender reputation, both IP and domain, is paramount. Even well-authenticated emails can go to spam if the sender's reputation is poor due to high complaint rates or spam trap hits.
Engagement matters: Consistent positive engagement (opens, clicks, replies) builds trust, while low engagement or high deletions/spam reports erode it, impacting future deliveries.
Proactive monitoring: Regular monitoring of deliverability metrics through tools like Google Postmaster Tools is crucial for early detection of issues before they escalate.
Key considerations
Leverage Postmaster Tools: Use Google Postmaster Tools to gain insights into your domain and IP reputation, spam rates, feedback loops, and authentication errors.
Review blocklist status: Perform regular blocklist checks (both public and private) for your sending IPs and domains, as a listing can severely impact deliverability.
Segment audiences: If sending marketing emails, segmenting your audience based on engagement and sending more frequently to highly engaged users can improve overall sender reputation with Gmail.
Content and formatting: While less common for one-to-one, ensure your email content avoids spammy phrases, excessive images, or poor HTML formatting that could trigger filters. Review common spam triggers.
Expert view
Expert from SpamResource.com advises that email filters are complex systems that use various data points to make decisions. It's not just about one factor like authentication, but a combination of sender reputation, content, and recipient engagement. This multi-faceted approach means deliverability issues often require a holistic troubleshooting strategy. Senders must consider how all these elements interact to influence inbox placement, especially when dealing with advanced filters like those employed by Gmail and G Suite.
10 Mar 2024 - SpamResource.com
Expert view
Expert from Wordtothewise.com suggests that mailbox providers continuously adjust their filtering algorithms to combat evolving spam tactics. What worked yesterday might not work today, making ongoing monitoring and adaptation essential for senders. These changes can sometimes inadvertently affect legitimate mail, leading to temporary spikes in spam placement for even well-behaved senders who might otherwise have a good sender reputation.
15 Feb 2024 - Wordtothewise.com
What the documentation says
Official documentation from Google and other authoritative sources consistently emphasizes the sophisticated nature of their spam prevention systems. They detail the multi-layered approach to identifying and blocking unwanted emails, which goes beyond basic authentication checks to include advanced machine learning, sender reputation analysis, and real-time threat intelligence.
Key findings
AI-powered defenses: Gmail's systems block a vast majority of spam, phishing, and malware using artificial intelligence and machine learning, constantly adapting to new threats.
Authentication standards: Strong email authentication (SPF, DKIM, DMARC) is a fundamental requirement for senders to ensure deliverability and build trust with Google's systems.
New sender requirements: Google has tightened enforcement efforts, particularly for bulk senders, requiring strict adherence to authentication, low spam rates, and easy unsubscribe options.
User feedback loops: Google uses feedback from users marking emails as spam to refine its filters and identify suspicious sending patterns.
Key considerations
Comply with standards: Ensure your email setup fully complies with Google’s sender guidelines, especially for DMARC implementation, as this is a critical trust signal.
Monitor spam complaints: A high spam complaint rate, even for a small percentage of recipients, will negatively impact your sender reputation and trigger filters. Aim for rates well below 0.1%.
Maintain positive engagement: Encourage recipients to open your emails, click on links, and reply. Low engagement signals can lead to emails being filtered to spam.
Review content and links: Avoid suspicious links or content that mimics phishing attempts, as Gmail’s AI is particularly adept at detecting these threats and may trigger warnings or spam placement.
Technical article
Documentation from Google's official blog outlines that Gmail's AI-powered defenses are highly effective, stopping more than 99.9% of spam, phishing, and malware from reaching user inboxes. This extremely high success rate is a testament to the sophistication of their filtering systems. The sheer volume of unwanted emails blocked, nearly 15 billion daily, underscores the constant battle against malicious senders and the importance of robust defenses that continually evolve to counter new threats.
06 Feb 2024 - blog.google
Technical article
Documentation from the Google Workspace Blog highlights the use of TensorFlow, Google's open-source machine learning framework, to catch spammers who manage to slip through the initial filters. This advanced capability targets the less than 0.1% of unwanted messages that are harder to detect with conventional methods. The aim is to enhance spam detection without inadvertently blocking important emails, demonstrating a continuous effort to refine accuracy and minimize false positives for legitimate senders.
