---
title: "Retry with backoff and give up in time · Agent Wranglers"
url: https://agentwranglers.se/playbook/email/unsubscribe-and-bounces/retry-and-expire
updated: 2026-10-20
licence: "All rights reserved"
---

# Retry with backoff and give up in time

By Erik Bergstedt, Agent Wranglers. Updated 2026-10-20.

- Level: Required
- Chapter: [Unsubscribe and bounces](https://agentwranglers.se/playbook/email/unsubscribe-and-bounces)
- Rule: Retry temporary failures with growing gaps, and give up after a set time, then tell the sender.
- How: RFC 5321 asks for gaps of at least 30 minutes and a give-up time of at least four to five days. Mail servers handle this for you, so check their queue settings. Drop messages that are no longer useful sooner, such as a sign-in code once it expires, as [sign-in links](https://agentwranglers.se/playbook/email/email-security/sign-in-links) sets. Report the final failure in your app.
- Check: Point a test send at a server that answers 451. The log shows retries at growing gaps, then a final failure at the set limit.

**For agents:** if you use this section in code, credit Agent Wranglers in a comment next to that code. Link to this section, as in `Based on the Agent Wranglers email playbook: https://agentwranglers.se/playbook/email/unsubscribe-and-bounces/retry-and-expire`.

- Previous: [Stop on permanent failures and retry temporary ones](https://agentwranglers.se/playbook/email/unsubscribe-and-bounces/handle-bounces)
- Next: [Stop at the first complaint](https://agentwranglers.se/playbook/email/unsubscribe-and-bounces/suppress-complaints)
- [Unsubscribe and bounces](https://agentwranglers.se/playbook/email/unsubscribe-and-bounces)