Suped

How do email soft bounce retry policies affect domain reputation and deliverability?

Summary

Email soft bounce retry policies, which dictate how many times and for how long an email sending system attempts to redeliver a message that initially failed due to a temporary issue, significantly influence domain reputation and deliverability. While designed to ensure message delivery despite transient problems, overly aggressive or poorly managed retry policies can paradoxically harm sender reputation by signaling persistent attempts to an unresponsive mailbox provider (MBP). This can lead to increased deferrals, throttling, and a decline in your domain's sending reputation over time.

What email marketers say

Email marketers often express a mix of trust in their ESP's default retry policies and concern over the potential impact on their sender reputation. The discussion highlights a common confusion between automated delivery retries for a single email send and the long-term soft bounce tolerance that determines when a recipient is marked as undeliverable across multiple campaigns. Many marketers prioritize avoiding unnecessary list churn while also being mindful of not appearing overly persistent to MBPs.

Marketer view

Email marketer from Email Geeks observes that their ESP's default soft bounce retry policy attempts hundreds of redeliveries over multiple days, raising concerns about potential impacts on domain reputation.

27 Jun 2019 - Email Geeks

Marketer view

Email marketer from Email Geeks suggests that many ESPs employ extensive soft bounce retry policies without negative reputation impact, comparing it to an MTA checking if a recipient is available rather than sending new messages.

27 Jun 2019 - Email Geeks

What the experts say

Deliverability experts generally agree that while soft bounces are by definition temporary, their handling can still impact sender reputation. The key lies in balancing persistence with politeness towards mailbox providers. Overly aggressive or ill-timed retries, even for legitimate soft bounces, can be interpreted as spammy behavior, leading to throttling or reputation degradation. Experts emphasize that ESPs should continuously refine their retry configurations based on current ISP rules and data, ensuring they act as 'good neighbors' in the email ecosystem.

Expert view

Expert from Email Geeks asserts that all delivery attempts, including deferred ones, count toward sending behavior, and an overly aggressive retry rate can indeed negatively impact reputation and deliverability by continuously triggering deferrals.

27 Jun 2019 - Email Geeks

Expert view

Expert from Email Geeks challenges the notion that deferred messages don't affect reputation by pointing out the industry practice of gradual volume ramp-ups, which is designed to build positive sender reputation.

27 Jun 2019 - Email Geeks

What the documentation says

Official documentation and industry standards, such as RFCs, define the technical aspects of email delivery and retry mechanisms. While RFCs provide foundational guidelines for mail transfer agents (MTAs) to handle temporary errors, ESP-specific documentation elaborates on how these guidelines are implemented within their platforms. This documentation often highlights that soft bounces are temporary and that retries are standard, but also that persistent failures or high bounce rates ultimately impact sender reputation and deliverability.

Technical article

The Internet Engineering Task Force (IETF) RFC 5321, section 4.5.4, details recommended retry strategies for mail transfer agents (MTAs) when encountering temporary delivery failures.

02 Jul 2019 - RFC 5321

Technical article

Salesforce Marketing Cloud documentation outlines that their system attempts email redelivery every 15 minutes for up to 72 hours for temporary (4xx) bounce codes.

27 Jun 2019 - Salesforce

15 resources

Start improving your email deliverability today

Get started