Overview

A mailing may issue a transient failure across all of its recipients, where the message Unable to merge the recipient's decoded parts for mail merging is found in the log.

Information

This is a known bug for ListManager 12.3.9 for email submitted content messages and merge tags.

To fix that issue, update your Lyris LM instance to version 12.4.1 or newer.

As a workaround, while you cannot update, avoid using merge tags in email submitted content messages.