Should I resend emails that hard bounced during the Gmail outage?

Key findings

• False positives: Many hard bounces (5.1.1 errors) reported during the Gmail outage were temporary delivery failures, not indications of invalid addresses. Google itself recommended re-sending these emails.
• Sender reputation: Normally, sending to hard bounces damages your sender reputation. However, in this unique circumstance, failure to re-send could mean missing engagement opportunities without significant negative impact if done carefully.
• Timeframe: The issue primarily affected December 14th, 2020, with some lingering effects on December 15th.
• Re-validation: It was advised to re-validate all Gmail bounces from that specific period, not just those with a 5.1.1 error code.

Key considerations

• Targeted re-sending: Only consider re-sending to Gmail addresses that hard bounced during the specific outage window. Do not apply this logic to hard bounces from other periods or domains.
• Bounce management: For general bounce management, always remove hard-bounced addresses from your list to maintain good sender reputation. This specific outage was an exception to the rule.
• Monitoring: Closely monitor your bounce rates and deliverability after re-sending. While the risk was low for this specific event, any re-engagement strategy requires careful observation.
• Google's recommendation: The fact that Google itself suggested re-sending emails affected by their outage, as noted in their public post-mortem, provides strong justification for this unusual step.

Key opinions

• Temporary issue: Many marketers quickly identified that the hard bounces were a result of Google's temporary service issues, not invalid addresses.
• Resend recommended: There was a strong sentiment among marketers to re-send to these affected Gmail addresses to ensure message delivery.
• Impact on lists: Some marketers noted an increase in 'held' records for Gmail domains in their ESPs due to the surge in these temporary hard bounces.
• Reputation concern: While cautious about sender reputation, the unique circumstances of a global outage mitigated the typical risks associated with re-sending to hard bounces. Ignoring Google's advice to resend could be a missed opportunity, especially when considering the differences between hard and soft bounces in normal scenarios.

Key considerations

• List segmentation: Marketers should segment their bounce data by date and domain to identify only the affected Gmail addresses from the outage period.
• ESP re-engagement: If using an ESP that automatically suppresses hard bounces, marketers might need to manually reactivate these specific Gmail addresses for re-sending.
• Post-outage analysis: It is crucial to analyze email campaign performance after the outage. For instance, understanding what causes sudden spikes in bounce rates is essential for future incident response.
• Beyond the outage: While the outage was an exception, marketers must generally adhere to strict list hygiene and remove hard bounces to protect their sender reputation and deliverability.

Key opinions

• Resend necessary: Experts strongly recommended re-sending to Gmail addresses that hard bounced during the outage, citing Google's own post-mortem advice.
• False-positive identification: The high volume of bounces observed relative to normal rates indicated a significant number of false positives.
• Re-validation process: It was considered easier and effective to re-validate all Gmail bounces from the period, rather than trying to filter for specific error messages.
• Minimal impact: The few genuine hard bounces (those truly invalid) would simply bounce again, without causing significant harm to sender reputation due to the extraordinary circumstances. This reinforces the need to manage hard bounced email addresses proactively in normal conditions.

Key considerations

• Context is key: The advice to re-send is highly specific to the documented Gmail outage. It does not apply to regular hard bounces or other temporary issues.
• Reviewing logs: Organizations should review their bounce logs from the precise dates of the outage (December 14th and 15th, 2020) to identify affected addresses.
• Deliverability best practices: While an exception, the event underscores the importance of a robust deliverability strategy, including continuous monitoring of bounce rates and sender reputation.
• Outage specifics: Understanding the exact nature of the outage is crucial for making informed decisions. Mailgun's perspective on hard bounces as permanent failures provides a contrast to the outage scenario.

Key findings

• Outage-specific advice: Google's support documentation directly addressed the issue, advising users to re-send emails that experienced delivery issues to valid @gmail.com addresses during the outage.
• Hard bounce definition: Standard documentation defines hard bounces as permanent delivery failures, implying no re-send attempts should be made. This case was a notable deviation.
• System error distinction: The outage caused bounces that resembled permanent failures but were in fact temporary system errors, which is critical for understanding the appropriate response.
• Reputation preservation: While consistent hard bounces can lead to a domain being added to a blacklist or blocklist, this scenario was an anomaly that Google itself green-lit for re-sending.

Key considerations

• Official advisories: Always refer to official post-mortems and support pages from major email providers during widespread outages.
• Understanding bounce codes: Even with common bounce codes like 5.1.1, context (e.g., a major service outage) can change their interpretation and the recommended action. Learn more about valid email addresses hard bouncing.
• Default rule: Despite this exception, the default rule remains that hard bounces signify permanent failures and should lead to the removal of the address from active mailing lists.
• Proactive monitoring: Maintaining a healthy sender reputation involves ongoing monitoring and swift action on bounce reports, as outlined in general deliverability guides, such as Mailgun's insights on hard bounces.