Emails - Bounce Lists

Introduction

Support teams often receive questions regarding bounce lists, why emails end up on a bounce list, and how to fix this issue. This article explains how emails end up on a bounce list and when to reach out to a support team with this type of issue. This information is useful to support and triage teams, as well as all other client-facing teams.

Background

Reward Gateway | Edenred uses Mailgun as the chosen mail delivery service provider. Mailgun uses a suppression system designed to maintain the integrity of the user's domain and IP. This is done by preventing delivery to addresses that have shown to be problematic for one of several possible reasons. Suppressions are performed on these addresses to protect the sender's ability to keep sending, and to keep their domain safe from Acceptable Use Policy (AUP) violations.

Types of Suppressions and How They're Organized

The three types of suppressions Mailgun implements are Bounces, Unsubscribes, and Complaints. They are organized by domain.

Bounces

Bounces happen when a recipient's address is returned as either invalid, non-existent, or temporarily misconfigured.

Unsubscribes

When a user no longer wants to receive emails, they can click the Unsubscribe option.

Complaints

Complaint-based suppressions happen when the receiver complains about the emails they are receiving. They do so by marking the emails as spam.

Removing Problematic Addresses

It's recommended to regularly remove addresses that have ended up on the Mailgun Suppressions from your contact list. Only removing them from the Suppressions list will start the process over. If you want to make sure you are no longer sending to these addresses, they need to be removed directly from the contact list.

What To Do Upon Receiving This Error - Not Delivering to Previously Bounced Address

Receiving this error message means that the email address you attempted to send an email to is being suppressed by the Mailgun system. This happens if, during a previous sending attempt, the recipient's email provider returned an error stating that this address doesn't exist or is invalid.

What To Do

As the first step, make sure that your clients and their IT teams (if they are using business email addresses) attempt to troubleshoot the issue.

1. Confirm that the email address you are attempting to send to is correct.
2. Confirm that the email address you are attempting to send to exists.
3. If there is a soft bounce due to the fact that the recipient's inbox is full, make sure the recipient frees up space for new emails.
4. Check if the issue is due to a DNS misconfiguration.
5. Check if the issue is due to filters or spam settings.

If you have gone through these steps and are sure that the recipient's address exists and any issues they may have had with their mailbox have been resolved, re-attempt sending the email. If the problem persists after you have made these troubleshooting efforts, you can reach out to the Product Support Team for further assistance.