Summary
The sudden routing of Postmark transactional emails to Gmail's spam folder was recently confirmed as a widespread issue, affecting multiple users and acknowledged by Postmark, which later announced its resolution. Beyond this specific event, such deliverability problems often stem from a damaged sender reputation, which can be influenced by increased spam complaints, high bounce rates, and authentication failures. Gmail's stricter policies for bulk senders, requiring proper DMARC alignment, low spam rates, and one-click unsubscribe options, also play a crucial role. Other factors include problematic email content, sudden increases in sending volume without proper warm-up, poor list quality, and issues with shared IP addresses impacting reputation.
Key findings
- Widespread Outage Confirmed: A global deliverability issue specifically affected Postmark transactional emails sent to Gmail, causing them to land in spam for many users. This issue was acknowledged and later resolved by Postmark, with client emails returning to the main inbox.
- Sender Reputation Critical: Gmail's spam filtering is highly sensitive to sender reputation, which can be negatively impacted by increased spam complaints, high bounce rates, and a lack of recipient engagement, even for transactional emails.
- Stricter Gmail Policies: Newer Gmail policies for bulk senders, including transactional senders, rigorously enforce DMARC alignment, a spam rate below 0.1%, and one-click unsubscribe. Non-compliance or authentication failures (SPF, DKIM, DMARC) are common culprits for spam placement.
- Content & Volume Triggers: Changes in email content, such as spammy keywords, unusual formatting, or excessive links, or sudden, significant increases in sending volume without proper warm-up, can trigger Gmail's spam filters.
- Shared IP Pool Risks: Problems with the shared IP pool used by an Email Service Provider like Postmark can sometimes lead to sudden deliverability issues, as poor sending practices by other users can negatively affect collective IP reputation.
Key considerations
- Monitor Reputation Tools: Regularly use Google Postmaster Tools to monitor your domain and IP reputation, spam rates, and delivery errors, as early warnings can prevent widespread deliverability issues.
- Verify Authentication: Routinely check and ensure the correct configuration and alignment of SPF, DKIM, and DMARC DNS records to prevent authentication failures, which Gmail strictly enforces.
- Maintain List Hygiene: Actively manage your email lists to minimize invalid or inactive addresses, as high bounce rates and spam complaints severely degrade sender reputation.
- Optimize Content: Review transactional email content for elements that might trigger spam filters, such as excessive caps, broken links, or an imbalanced image-to-text ratio, and personalize where possible.
- Warm-Up New Sending: Implement proper warm-up procedures for new domains, IP addresses, or significant increases in sending volume to avoid sudden flags from Gmail's filters.
- Utilize Feedback Loops: Leverage Feedback Loops (FBLs) to stay informed about spam complaint rates from Gmail users, enabling proactive adjustments to sending practices.
What email marketers say
13 marketer opinions
Beyond a recent, confirmed global deliverability issue impacting Postmark transactional emails to Gmail, several factors can cause even essential messages to suddenly land in spam. These include changes in email content- such as spammy keywords, unusual formatting, or excessive links- and sudden, significant increases in sending volume or drastic shifts in sending patterns without proper warm-up. Poor recipient engagement, characterized by persistently low open or click-through rates, can degrade sender reputation over time. Additionally, a high number of invalid or stale email addresses leading to increased bounce rates, problems with the shared IP pool impacting collective reputation, and even subtle inconsistencies in the sender's 'From' name or address can trigger Gmail's spam filters for transactional messages.
Key opinions
- Confirmed Postmark Outage: Multiple email marketers and Postmark support confirmed a widespread, global deliverability problem causing Postmark transactional emails to land in Gmail spam, which was later announced as resolved.
- Broadcast & Transactional Impact: The confirmed deliverability issue with Postmark affected both broadcast and transactional email streams, indicating a broad platform-level problem rather than one isolated to a specific email type.
Key considerations
- Monitor Platform Status: In cases of sudden, widespread deliverability issues, check your Email Service Provider's status page, such as Postmark's, for confirmed outages and resolutions impacting Gmail delivery.
- Content Element Scrutiny: Regularly audit transactional email content for subtle spam triggers like excessive use of all caps, multiple exclamation marks, broken links, hidden text, or an imbalanced image-to-text ratio, as these can flag messages even if legitimate.
- Gradual Sending Volume: Implement a gradual warm-up process for new domains, IP addresses, or significant increases in sending volume to avoid triggering Gmail's suspicious activity alerts for sudden, drastic changes in sending patterns.
- Prioritize User Engagement: Focus on fostering recipient engagement with your transactional emails; persistently low engagement rates can signal to Gmail that messages are undesirable, degrading sender reputation over time.
- Maintain Sender Identity: Ensure consistency in the 'From' name and email address, and if changes are necessary, properly warm up the new sender identity to avoid temporary flagging by Gmail's filters.
- Continuous List Cleaning: Regularly clean and validate your email lists to remove invalid or stale addresses, preventing high bounce rates that negatively impact sender reputation with Gmail.
Marketer view
Email marketer from Email Geeks shares a Reddit thread and personal account warnings, indicating that the Postmark deliverability issue affecting Gmail spam placement appears to be a wider, confirmed problem affecting other users.
3 Dec 2024 - Email Geeks
Marketer view
Email marketer from Email Geeks, a Postmark support team member, confirms that the deliverability issue is part of a wider problem that the team is aware of, with an update to their status page expected soon.
28 Feb 2022 - Email Geeks
What the experts say
3 expert opinions
The current consensus points to sender reputation as the primary driver behind transactional emails unexpectedly landing in Gmail's spam folder, even when sent via reliable services like Postmark. This reputation can be severely damaged by factors such as an increase in spam complaints, a decline in recipient engagement, or a rise in bounce rates from invalid addresses. Furthermore, issues with email authentication protocols like SPF, DKIM, and DMARC can directly impact deliverability. While often sender-driven, experts also highlight the possibility of underlying provider-side problems, such as misconfigured reverse DNS (rDNS), which can have a widespread and immediate negative impact on delivery.
Key opinions
- Sender Reputation Degradation: A sudden drop in deliverability, even for transactional emails, typically signals a decline in sender reputation, influenced by factors like increased spam complaints, lower engagement, or higher bounce rates.
- Authentication Protocol Issues: Failures or misconfigurations in SPF, DKIM, or DMARC authentication can cause Gmail to flag legitimate emails as spam.
- Underlying Provider-Side Problems: Less commonly, issues like rDNS misconfiguration on the Email Service Provider's side can lead to sudden and severe deliverability problems for all emails sent through that provider.
- Content and Recipient Quality: Even transactional messages can be flagged due to content that triggers spam filters or due to sending to a high volume of unknown or invalid recipients.
Key considerations
- Utilize Google Postmaster Tools: Actively monitor domain and IP reputation, spam complaint rates, and delivery errors within Google Postmaster Tools for early detection of issues.
- Verify Email Authentication: Regularly audit and confirm the correct setup and alignment of SPF, DKIM, and DMARC records to ensure proper email authentication.
- Address Recipient List Health: Continuously clean email lists to remove invalid or unengaged recipients, thereby reducing bounce rates and spam complaints.
- Review Email Content: Scrutinize transactional email content for any elements that might inadvertently trigger spam filters, despite the message's legitimate nature.
- Investigate Provider-Side Status: If self-checks yield no issues and the problem is sudden and widespread, investigate whether the ESP, like Postmark, is experiencing a known issue or system-wide misconfiguration.
Expert view
Expert from Email Geeks suggests checking Google Postmaster Tools for reputation and complaint rates, and verifying DKIM and DMARC authentication when facing deliverability issues. She later acknowledges that the reported symptoms sound like a known issue, suggesting a potential provider-side problem like rDNS misconfiguration, which can severely impact delivery.
11 Jul 2023 - Email Geeks
Expert view
Expert from Spam Resource explains that even transactional emails, including those sent through services like Postmark, can suddenly land in Gmail spam due to underlying issues such as sending to unknown or invalid recipients, using content that triggers spam filters, or problems with the sending IP's reputation, even if the Email Service Provider (ESP) is generally reliable.
1 Nov 2023 - Spam Resource
What the documentation says
6 technical articles
When Postmark transactional emails abruptly shift to Gmail's spam folder, it often signifies a significant hit to sender reputation, a core factor Gmail considers for email placement. This decline can stem from an increase in spam complaints, high bounce rates, or critical failures in email authentication protocols such as SPF, DKIM, and DMARC. Gmail's updated, stringent policies for all bulk senders, including those with transactional emails, now demand strict adherence to DMARC alignment, a sub-0.1% spam rate, and a visible one-click unsubscribe option. Failure to comply with these rules or any recent misconfigurations in DNS authentication records will directly lead to messages being flagged as suspicious. Moreover, a lack of consistent monitoring using tools like Google Postmaster Tools and a failure to utilize Feedback Loops can prevent senders from detecting early warnings, allowing reputation issues to escalate and trigger widespread spam filtering.
Key findings
- Reputation Damage: A sudden drop in transactional email deliverability to Gmail is often a direct result of a damaged sender reputation, stemming from issues like increased spam complaints or high bounce rates.
- Authentication Missteps: Even minor, incorrect changes or misconfigurations in SPF, DKIM, or DMARC DNS records can lead to immediate authentication failures with Gmail, causing emails to be classified as spam.
- Strict Gmail Policies: Gmail's updated guidelines for bulk senders now mandate DMARC alignment, maintaining a spam rate below 0.1%, and offering a one-click unsubscribe, with non-compliance directly impacting deliverability.
- Monitoring Gaps: Inadequate use of Google Postmaster Tools and a failure to leverage Feedback Loops (FBLs) prevent senders from proactively addressing rising spam complaints or declining reputation, leading to sudden spam folder placement.
Key considerations
- Prioritize Sender Reputation: Actively manage factors that influence sender reputation, such as minimizing spam complaints and reducing bounce rates through vigilant list hygiene.
- Validate Authentication Records: Regularly review and confirm that SPF, DKIM, and DMARC DNS records are correctly configured and aligned to prevent authentication failures with Gmail.
- Adhere to Gmail's Requirements: Ensure full compliance with Gmail's bulk sender policies, specifically DMARC alignment, maintaining a low spam rate, and implementing the one-click unsubscribe option.
- Leverage Monitoring Tools: Consistently utilize Google Postmaster Tools and Feedback Loops to monitor domain and IP reputation, track spam complaints, and identify delivery errors early.
Technical article
Documentation from Postmark Support Center explains that a sudden decline in Postmark transactional email deliverability to Gmail often points to a damaged sender reputation. This damage can result from an increase in spam complaints, high bounce rates, or issues with critical authentication protocols like SPF, DKIM, or DMARC, leading Gmail to flag emails as suspicious.
16 Jun 2023 - Postmark Support Center
Technical article
Documentation from Google Workspace Admin Help emphasizes that updated Gmail policies for bulk senders, including those sending transactional emails, now strictly require proper DMARC alignment, maintaining a spam rate below 0.1%, and implementing a one-click unsubscribe option. Non-compliance with these guidelines can directly lead to emails being marked as spam in Gmail.
19 May 2022 - Google Workspace Admin Help
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