What does SES bounce code 60 specifically mean?

Amazon SES bounce code 60 typically indicates an auto-reply or out-of-office message. It means the email was delivered to the recipient's server but was met with an automated response rather than a human interaction.

How does bounce code 60 affect my sender reputation?

While less severe than hard bounces or spam complaints, a sustained high rate of bounce code 60 can indicate issues with list hygiene or an unengaged audience, potentially impacting your overall sender reputation .

Should I remove addresses that generate bounce code 60 from my lists?

It's generally not necessary to immediately remove addresses for bounce code 60, as the issue is often temporary. However, if an address consistently generates these bounces over time and shows no engagement, it might be beneficial to consider suppressing it.

Can seasonality cause an increase in bounce code 60?

Yes, seasonality, such as holidays or vacation periods, frequently leads to a natural increase in auto-reply messages, and consequently, a rise in bounce code 60 as more people use out-of-office responders.

What tools can help me monitor bounce rates from Amazon SES?

While I cannot recommend specific tools, monitoring your Amazon SES bounce notifications and detailed logs is crucial for understanding bounce patterns. Integrating this data with your email analytics can provide a holistic view.

Why am I seeing an increase in bounce code 60 from SES? - Troubleshooting - Email deliverability - Knowledge base

I've been hearing from a number of senders recently about a specific issue with Amazon SES: an unexpected increase in bounce code 60. This can be quite puzzling, especially when your email metrics suddenly shift. If you're seeing a spike in these bounces, you're not alone, and it's a good idea to understand what this code signifies and how to address it.

When we talk about email bounces, we usually categorize them into hard bounces and soft bounces. Hard bounces mean the email address is permanently invalid, while soft bounces are temporary issues. An increase in any bounce type warrants attention, as it can negatively impact your sender reputation and lead to reduced inbox placement.

Understanding bounce code 60 in SES

Amazon SES classifies various types of delivery failures and sends notifications with specific bounce codes. Bounce code 60, in particular, is often associated with auto-reply messages. These aren't typically indicative of an invalid email address in the same way a hard bounce is, but rather an automated response from the recipient's mailbox indicating that the email was received but handled by an automated system, like an out-of-office reply or a vacation responder.

While an auto-reply doesn't mean the email couldn't be delivered, Amazon SES categorizes it as a type of bounce because it signifies that the message did not reach an actively monitored inbox from a human. For certain campaigns or transactional emails, receiving an automated reply instead of direct engagement can still be considered a non-delivery from a business perspective.

The good news is that bounce code 60 is generally less damaging to your sender reputation than hard bounces or spam complaints. However, a significant increase in these bounces can still signal underlying issues, such as targeting inactive users or sending during periods when recipients are likely to be away. It's a metric that shouldn't be ignored, especially if it's trending upwards.

Common causes for the increase

Several factors can contribute to a sudden increase in bounce code 60. One common reason is seasonality. During major holidays, school breaks, or peak vacation seasons, more people set up out-of-office replies, leading to a natural surge in these bounces. If your increase aligns with such a period, it might be a temporary effect.

Changes in your audience or sending patterns can also play a role. If you've recently started sending to a new segment of your list, particularly corporate or academic domains, those recipients might have more stringent auto-reply systems or be more prone to setting out-of-office messages. An older list, or one not regularly updated, could also contain a higher percentage of inactive mailboxes that trigger automated responses.

Sometimes, the way a recipient's email server is configured can influence how these auto-replies are categorized by SES. While less common, certain server setups might return a response that SES interprets as a generic bounce code 60, even if it's primarily an informational auto-reply. Understanding these nuances is key to identifying the root cause.

Diagnosing and troubleshooting the increase

When you notice an increase in bounce code 60, the first step is to thoroughly investigate your Amazon SES bounce logs. Look for patterns: are the bounces coming from specific domains, particular campaigns, or during certain times of the day? Detailed log analysis can help you pinpoint if the issue is widespread or isolated.

It's also crucial to compare the bounce code 60 trend with your other deliverability metrics. Are you also seeing an increase in hard bounces, soft bounces, or complaint rates? If other metrics are rising, the bounce code 60 increase might be a symptom of a broader deliverability issue, such as poor sender reputation or emails going to spam.

Consider if any recent changes to your sending infrastructure, content, or list acquisition methods could be contributing factors. Even minor adjustments can sometimes have unforeseen impacts on how recipients' mail servers respond to your messages. This includes reviewing your email authentication. Ensure your DMARC, SPF, and DKIM records are correctly configured and aligned.

Investigating SES bounce code 60

Recipient server responses: Analyze the detailed bounce messages associated with code 60 within your SES console or logs to see the specific responses from recipient mail servers.
Segment analysis: Determine if the increase in bounces is coming from a specific email list, campaign, or geographic region.
Sending patterns: Review recent changes in your sending volume, frequency, or content to identify any correlations.

Strategies for mitigation

While you can't prevent people from setting auto-replies, you can take steps to mitigate the impact of bounce code 60 on your overall deliverability. One key strategy is robust list hygiene. Regularly cleaning your email lists of inactive or unengaged subscribers can reduce the number of auto-replies you encounter. Focus your sending on engaged subscribers who actively open and click your emails.

Consider implementing engagement-based sending by segmenting your audience based on recent activity. This ensures you're primarily reaching active inboxes, minimizing automated responses. For recipients who consistently generate bounce code 60, especially if they are not converting, it might be beneficial to move them to a re-engagement segment or suppress them entirely if they remain unresponsive.

While not directly related to auto-replies, maintaining a strong sender reputation is always paramount for overall email deliverability. This includes monitoring for any potential blacklist (or blocklist) issues, as a poor reputation can lead to more general delivery challenges, including a higher rate of ambiguous bounces. Ensuring that you are adhering to Amazon SES best practices for sending is also crucial for preventing broader deliverability problems. My experience has been that healthy sending practices help mitigate various bounce types.

Regularly review your suppression lists within SES. Addresses that consistently generate bounces, even soft ones or auto-replies, should be considered for removal if they are not providing value to your communications. This proactive approach helps to keep your lists clean and your bounce rates manageable, ultimately improving your overall inbox placement.

Views from the trenches

Best practices

Regularly audit your email lists to remove inactive or unengaged subscribers, focusing on active recipients.

Segment your audience based on engagement levels to send more targeted and relevant campaigns.

Monitor specific bounce messages and patterns, not just the bounce codes, to understand the root cause.

Review your email authentication (SPF, DKIM, DMARC) to ensure proper configuration and alignment.

Common pitfalls

Ignoring auto-reply bounces, as they can indicate list quality issues or unoptimized sending times.

Assuming all bounce code 60s are harmless; a high volume can still impact your sender reputation.

Failing to adapt sending strategies during holiday seasons or peak vacation periods.

Not integrating bounce data with your customer engagement metrics to identify truly inactive users.

Expert tips

Utilize engagement data to refine your sending strategy and prioritize subscribers who actively interact with your emails.

Pay close attention to changes in recipient server behavior and adjust your sending practices accordingly.

Implement a re-engagement strategy for subscribers who frequently trigger bounce code 60 before suppressing them permanently.

Keep an eye on global deliverability trends, as changes by major mailbox providers can affect bounce classifications.

Marketer view

Marketer from Email Geeks says they would need more data to confirm any aggregate trend in this behavior.

2025-10-01 - Email Geeks

Marketer view

Marketer from Email Geeks says it might simply be a random code assigned to out-of-office replies.

2025-10-01 - Email Geeks

Keeping your email health in check

An increase in bounce code 60 from Amazon SES, while seemingly benign, serves as a reminder to consistently monitor your email deliverability metrics. These bounces, often related to auto-replies, can signal shifts in your audience's activity or underscore the need for more granular list management.

By actively diagnosing the cause, implementing strong list hygiene, and maintaining overall email health, you can ensure that your messages reach their intended recipients effectively and that your sender reputation remains strong. Proactive management of your email program is always the best defense against unexpected deliverability challenges.