What does Gmail's grey warning bar mean and why does it appear?
Matthew Whittaker
Co-founder & CTO, Suped
Published 10 Jul 2025
Updated 16 Aug 2025
9 min read
Receiving an email in Gmail that displays a grey warning bar can be unsettling, especially if it's from a sender you trust. This seemingly simple bar carries a significant message about how Gmail's spam filters are assessing the email, even when it lands in your inbox due to specific organizational or personal settings. It often indicates that Gmail's algorithms initially flagged the message as potentially suspicious or spam, but a rule intervened to deliver it anyway.
This warning is a proactive measure by Google to keep users informed about potential risks. It signals that while the email was delivered, it bypassed some standard security checks or triggered internal thresholds. Understanding the underlying reasons for this grey warning bar is crucial for both recipients, who should exercise caution, and senders, who need to address their email deliverability practices to avoid being flagged.
What the grey warning bar signifies
The grey warning bar in Gmail typically appears when an email's initial risk assessment by Gmail's powerful spam filters (which learn and adapt) indicates it could be spam, but a user-defined or organizational rule overrides that decision. The message displayed, such as "This message was not sent to Spam based on your organization's settings," confirms this override. This means that for a regular Gmail user without such a rule, the email would very likely have ended up in the spam folder. More information on Gmail's spam filter behavior can provide further context.
This often occurs within corporate or educational environments where administrators have set up specific allowlist (or whitelist) rules for certain senders or domains, even if Gmail itself deems the content or sender suspicious. The grey bar serves as a transparent warning to the end-user, indicating that while the email was delivered, it might still carry elements typically associated with spam or phishing attempts. It is a way for Gmail to say, "We think this is problematic, but your settings overrode our judgment."
Gmail's assessment
Gmail's internal machine learning models analyze various factors to determine if an email is suspicious, regardless of organizational rules.
Even with an override, Gmail wants to inform the user about its initial security assessment.
The distinction between internal organizational rules and Gmail's global spam filtering algorithm is key here. While an organizational rule might prevent an email from being quarantined or sent to spam within that specific domain, it does not change Gmail's underlying risk assessment. This means that if the same email were sent to a typical Gmail account outside of that organization, it would very likely be categorized as spam. This difference highlights the importance of maintaining a strong sender reputation for all recipients, not just those within specific organizational allowlists.
Common causes of the grey warning bar
Several factors can contribute to Gmail's decision to display the grey warning bar. These typically fall into categories related to sender reputation, email content, and authentication status. A poor sender reputation, perhaps due to a history of user complaints, low engagement, or being listed on a blocklist (or blacklist), is a primary culprit. Gmail's filters are designed to protect users from unwanted messages, and a history of suspicious sending practices will trigger these warnings. Understanding how Gmail's filters determine spam can help identify the root cause.
The content of the email itself also plays a critical role. Emails with suspicious links, common spam trigger words, unusual formatting, or attempts to impersonate legitimate entities can raise red flags. Gmail's algorithms are sophisticated enough to detect subtle patterns indicative of unsolicited or malicious mail. Even if the sender is legitimate, a poorly constructed email can inadvertently trigger these warnings. This is particularly true for marketing or transactional emails that might contain numerous links or unusual phrasing.
Positive authentication
SPF aligned: The sending IP address is authorized by the domain's SPF record.
DKIM signed: The email is digitally signed, verifying its integrity and sender.
DMARC enforced: A DMARC policy is properly configured and passes authentication checks.
These authentication protocols help establish trust with mail servers, reducing the likelihood of a grey warning bar.
Negative authentication
Missing SPF: No SPF record or misconfigured entries allow unauthorized sending.
Lack of proper authentication can significantly impact trust and lead to grey warning bars or even direct spam placement.
Crucially, a missing or misconfigured email authentication (SPF, DKIM, DMARC) can lead to Gmail displaying a grey warning bar. If Gmail cannot verify the sender due to authentication failures, it becomes highly suspicious, even if a rule dictates delivery. This is because proper authentication builds trust and signals that the email truly originated from the claimed domain, reducing the risk of spoofing or phishing.
Troubleshooting and prevention
For senders, addressing the root causes of the grey warning bar is essential for ensuring robust email deliverability to all Gmail recipients, not just those with specific allowlist rules. The first step is to strengthen your email authentication. Implementing or correctly configuring DMARC with a policy set to at least quarantine will provide valuable insights into your email ecosystem and ensure proper alignment of your SPF and DKIM records. Regularly checking your DMARC reports will help you identify any authentication failures.
Beyond authentication, focus on maintaining a pristine sender reputation. This involves actively monitoring your domain and IP address for inclusion on any blocklists (or blacklists), which can severely impact deliverability. A dedicated guide to email blocklists can provide comprehensive steps for remediation if you find yourself listed. Also, ensure your email content is clean, relevant, and avoids common spam triggers. Regularly clean your email lists to remove inactive or invalid addresses, as these can turn into spam traps, which are a significant contributor to reputation damage and subsequent warnings.
For ongoing prevention, consider utilizing tools like Google Postmaster Tools to keep an eye on your domain's health and deliverability metrics. These insights will help you proactively identify and address potential issues before they escalate into persistent grey warning bars or, worse, direct spam folder placement for all your emails.
Impact on email deliverability
The appearance of Gmail's grey warning bar, while sometimes mitigated by organizational rules, signals a fundamental issue with your email's perceived trustworthiness. For email deliverability, this means that your messages are not consistently achieving optimal inbox placement across all Gmail users. If an email is consistently flagged with this warning for general recipients, it indicates that Gmail's filters believe it belongs in spam. This can significantly reduce your email's visibility, engagement rates, and overall marketing effectiveness.
The cumulative effect of these warnings can also impact your long-term domain reputation. While individual users might bypass the spam folder with filters, the negative signals Gmail receives contribute to your sender score. A consistently low score can lead to more severe deliverability issues, such as emails being outright rejected or silently dropped, even without a visible warning bar. Therefore, proactively addressing the causes of the grey bar is crucial for ensuring that your emails consistently reach the inbox.
Recipient impact: The grey bar can confuse recipients and reduce trust in your emails.
Engagement rates: Warnings can lead to lower open and click-through rates.
Spam complaints: Even with an override, recipients might still mark messages as spam.
Ultimately, the grey warning bar is a clear signal from Gmail that something about your email, or your sending practices, needs attention. Ignoring it could lead to increasingly severe deliverability challenges in the future. Focusing on email authentication, content quality, and list hygiene are foundational steps to ensure your emails reach their intended destination without these cautionary flags.
Views from the trenches
Best practices
Ensure all your email authentication records (SPF, DKIM, DMARC) are correctly set up and aligned.
Regularly monitor your domain's reputation using tools like Google Postmaster Tools for any anomalies.
Keep your email lists clean and regularly remove inactive or invalid addresses to avoid spam traps.
Craft clear, concise email content, avoiding excessive links, suspicious phrasing, or known spam triggers.
Common pitfalls
Assuming an organizational allowlist means your emails are safe for all recipients, ignoring underlying deliverability issues.
Neglecting to monitor DMARC reports, thus missing critical insights into authentication failures.
Failing to address content-related issues that might trigger spam filters, such as overly promotional language.
Sending emails to unengaged recipients, which can lead to spam complaints and damage your sender reputation.
Expert tips
Implement a DMARC policy with at least 'quarantine' to actively manage how unauthenticated emails are handled.
Continuously test your email deliverability to various providers, including Gmail, to catch issues early.
Educate internal stakeholders on the importance of proper email sending practices and how they impact deliverability.
If you suspect an issue, conduct a thorough audit of your email infrastructure and sending practices.
Expert view
Expert from Email Geeks says the grey bar indicates Gmail's spam filters think an email is spam, and it's only in the inbox because of an organizational override. For external Gmail recipients, it would likely go to spam.
2021-06-24 - Email Geeks
Expert view
Expert from Email Geeks says this scenario is common in Google Workspace environments where rules move internal reports to specific folders, often triggering warnings due to URL injections.
2021-06-24 - Email Geeks
Summary and next steps
The grey warning bar in Gmail is more than just a visual quirk, it's a critical indicator of how Gmail's sophisticated spam filters perceive your email. While organizational or personal rules can override initial spam detection and deliver the email to the inbox, the warning bar itself signifies that Gmail considered the message suspicious. This perception is influenced by factors such as sender reputation, email content, and crucial email authentication protocols like SPF, DKIM, and DMARC.
For email senders, ensuring consistent inbox placement means proactively addressing these underlying issues. Strengthening your email authentication, diligently monitoring your domain's reputation for any blocklist (or blacklist) inclusions, and maintaining clean, engaging content are paramount. Ignoring these warnings can lead to a damaged sender reputation and, ultimately, significantly lower deliverability rates across all recipients, not just those with specific filters in place.
Gmail that displays a grey warning bar can be unsettling, especially if it's from a sender you trust. This seemingly simple bar carries a significant message about how Gmail's spam filters are assessing the email, even when it lands in your inbox due to specific organizational or personal settings. It often indicates that Gmail's algorithms initially flagged the message as potentially suspicious or spam, but a rule intervened to deliver it anyway.
Google Postmaster Tools to keep an eye on your domain's health and deliverability metrics. These insights will help you proactively identify and address potential issues before they escalate into persistent grey warning bars or, worse, direct spam folder placement for all your emails.
