Summary
High soft bounce rates during US Thanksgiving week are a common issue due to a confluence of factors. The holiday season brings increased email volume and competition for inbox space, straining email servers and leading to temporary issues like server overloads (indicated by SMTP 4xx errors) and full inboxes. ISPs also implement more aggressive filtering to combat holiday scams, which can inadvertently block legitimate emails. A surge in auto-replies and out-of-office messages further contributes to bounce rates. It's crucial to analyze bounce codes and NDRs to identify the specific reasons for the bounces, monitor sender reputation, and ensure proper email authentication (SPF, DKIM, DMARC). Specific issues highlighted include potential changes in Gmail's bounce messages and the importance of investigating 'exceeded max time' bounces originating from the sender's MTA. For Salesforce Marketing Cloud users, soft bounces may sometimes represent misclassified blocked bounces due to configuration issues. Overall, proactive list hygiene practices, segmentation, and adapting sending strategies are vital to mitigating the impact of these factors and maintaining healthy deliverability during peak sending times.
Key findings
- Increased Email Volume: Holiday season brings a surge in email volume, straining servers and filtering systems.
- Aggressive Filtering: ISPs implement stricter filtering rules to combat increased scam activity during the holidays.
- Auto-Replies: Vacation messages and auto-replies significantly contribute to soft bounce rates.
- SMTP 4xx Errors: Temporary SMTP errors (4xx codes) indicate server overload or temporary unavailability issues.
- NDRs: Non-Delivery Reports (NDRs) point to issues like server problems, full inboxes, or auto-replies.
- Sender MTA Bounces: The “exceeded max time” bounce reason indicates deferrals from the sender’s MTA warranting investigation.
- Poor Reputation: Sending to invalid email addresses, exceeding sending limits, and poor sender reputation significantly affects deliverability.
- Gmail Changes: Recent Gmail changes to bounce messages on or around November 20 might contribute to higher storage space bounces.
Key considerations
- Analyze Bounce Codes: Thoroughly analyze bounce codes and NDRs to pinpoint the root causes of bounces.
- Monitor Sender Reputation: Regularly monitor sender reputation metrics and delivery failures using tools like Google Postmaster Tools.
- Practice List Hygiene: Implement robust list cleaning and re-engagement campaigns to remove inactive subscribers.
- Segment Lists: Segment email lists based on engagement levels and tailor messaging accordingly.
- Ensure Authentication: Implement and maintain proper email authentication protocols (SPF, DKIM, DMARC) to improve deliverability.
- Investigate MTA Issues: Check ESP logs for deferral messages to diagnose any problems with the sender's MTA.
- Adjust Sending Strategy: Optimize sending times and adapt messaging to address increased competition and inbox clutter.
- Implement Retry Mechanisms: Implement retry mechanisms to handle temporary failures.
What email marketers say
14 marketer opinions
High soft bounce rates during US Thanksgiving week are a common issue due to a combination of factors. Increased email volume and inbox clutter during the holiday season put a strain on email servers and filters, leading to temporary server issues, deferrals, and full inboxes. More aggressive filtering by ISPs to combat holiday scams also contributes. A surge in auto-replies and out-of-office messages adds to the bounce rate. Analyzing bounce codes, reviewing sender reputation, and list hygiene practices are essential to mitigate the impact. Some specific issues called out were that Gmail made changes to bounce messages around November 20, resulting in an increase in 'storage space' bounces, and that the 'exceeded max time' bounce reason originates from the sender's MTA, potentially indicating deferral problems.
Key opinions
- Increased Volume: Holiday season brings higher email traffic, straining servers and filters.
- Gmail Changes: Gmail's bounce message updates around November 20 may contribute to higher 'storage space' bounces.
- Aggressive Filtering: ISPs implement stricter filtering to prevent scams and unwanted mail.
- Auto-Replies: Vacation messages and auto-replies surge during holidays, causing soft bounces.
- Sender Reputation: A poor sender reputation will significantly affect your email deliverability.
- MTA Bounce Origin: The 'exceeded max time' bounce indicates deferrals from the sender's MTA, warranting investigation.
Key considerations
- Analyze Bounces: Export and analyze bounce codes to identify root causes and domain-specific issues.
- Monitor Reputation: Regularly check sender reputation metrics and Google Postmaster Tools.
- Clean Lists: Implement list cleaning and re-engagement campaigns to remove inactive subscribers.
- Segment Lists: Segment lists based on engagement to prioritize active subscribers.
- Authentication: Ensure proper email authentication (SPF, DKIM, DMARC) to improve deliverability.
- ESP Logs: Check ESP logs for deferral messages to diagnose MTA-related bounce issues.
- Sending Times: Optimize sending times to minimize inbox clutter and competition.
- Consider Unique Addresses: Determine if bounce counts are unique addresses or if duplicates exist for the same address.
Marketer view
Email marketer from Sendinblue Blog shares that increased competition and inbox clutter during the holiday season can cause higher bounce rates. Strategies like list cleaning, re-engagement campaigns, and optimizing sending times are recommended to combat this.
25 Oct 2024 - Sendinblue Blog
Marketer view
Marketer from Email Geeks suggests that 862,548 soft bounces out of 4.3M is surprisingly high and suggests checking if a major provider is bouncing everything. They also mention that mailing a list that hasn't been mailed in a long time could be a factor.
23 Oct 2021 - Email Geeks
What the experts say
3 expert opinions
High soft bounce rates during US Thanksgiving week can be attributed to a few factors, even if the exact causes are not always directly related to the holiday itself. Deliverability declines during the holiday season due to increased email volume, straining filters and infrastructure, as well as more aggressive filtering due to higher risks of scams. While specifics depend on the email platform, such as Salesforce Marketing Cloud misclassifying blocked bounces as soft bounces, maintaining good deliverability, reputation and engagement are important factors that can cause issues especially around peak sending times when filters are more sensitive.
Key opinions
- General Holiday Decline: Deliverability tends to decrease during the holiday season due to increased email volume.
- Aggressive Filtering: ISPs implement more aggressive filtering during the holiday period to combat scams and unwanted mail.
- Platform-Specific Issues: Some platforms, like Salesforce Marketing Cloud, may misclassify blocked bounces as soft bounces due to configuration issues.
- Reputation & Engagement: Maintaining good deliverability, reputation and engagement are important factors that can cause issues especially around peak sending times when filters are more sensitive.
Key considerations
- Monitor Deliverability: Pay close attention to deliverability metrics during the holiday season.
- Investigate Bounce Types: Investigate the specific types of bounces and ensure that soft bounces are not misclassified blocked bounces.
- Improve Sender Reputation: Take steps to improve sender reputation to improve deliverability during periods of increased volume.
Expert view
Expert from Email Geeks explains that in Salesforce Marketing Cloud, soft bounces often mean blocked bounces, but the account isn't configured to separate them properly.
26 Feb 2022 - Email Geeks
Expert view
Expert from Word to the Wise explains that deliverability often declines during the holiday season. This isn't about Thanksgiving directly, but the general trend applies. Causes include increased overall email volume, which puts strain on filters and infrastructure, and more aggressive filtering due to the higher risk of scams and unwanted mail during the period.
22 Oct 2022 - Word to the Wise
What the documentation says
4 technical articles
High soft bounce rates can be caused by a multitude of temporary issues as indicated by SMTP 4xx error codes and Non-Delivery Reports (NDRs). These temporary issues include server overloads, server unavailability, or full recipient inboxes. High bounce rates can stem from more consistent issues, such as sending emails to invalid addresses, exceeding sending limits, or having a poor sender reputation. Implementing DMARC to enhance email authentication and prevent spoofing can improve deliverability and inbox placement, reducing bounce rates. Therefore, analysing bounce messages and NDRs is crucial to understand the nature of the bounces.
Key findings
- SMTP 4xx Errors: Temporary SMTP errors indicate transient issues such as server overload or unavailability.
- NDRs Indicate Issues: Non-Delivery Reports reveal temporary issues, including server problems, full inboxes, or auto-replies.
- Google Workspace Bounce Causes: Google Workspace high bounces are often due to invalid addresses, exceeding limits, or poor reputation.
- DMARC Enhances Deliverability: DMARC helps prevent spoofing, improving deliverability and reducing bounce rates.
Key considerations
- Check Bounce Messages: Review bounce messages and NDRs for specific error codes to diagnose the bounce causes.
- Address Invalid Addresses: Ensure email lists are up-to-date and remove or correct invalid email addresses.
- Respect Sending Limits: Adhere to sending limits imposed by email providers to avoid being flagged as spam.
- Improve Sender Reputation: Take steps to improve sender reputation through responsible sending practices and engagement with recipients.
- Implement DMARC: Implement DMARC to authenticate emails, prevent spoofing, and improve deliverability.
Technical article
Documentation from Google Workspace Admin Help shares that high bounce rates in Google Workspace can stem from several issues, including sending to invalid email addresses, exceeding sending limits, or having a poor sender reputation. Google recommends checking bounce messages for details.
29 Dec 2023 - Google Workspace Admin Help
Technical article
Documentation from RFC 5321 explains that temporary SMTP errors (4xx codes) can indicate temporary issues like server overload or temporary unavailability. Repeated 4xx errors might result in delayed delivery or bounces.
11 Jun 2025 - RFC 5321
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