This feature is intended to prevent mailbox congestion after sending a communication. Specifically this feature will suppress certain messages such as out of office replies and auto replies that are rule based, as well as soft Delivery/Nondelivery reports. This feature can be enabled by doing the following
1. Open a new Message
2. Click the PoliteMail Flag
3. Choose Suppress Auto-Replies
Some messages cannot easily be suppressed. These messages are typically bounces or hard NDRs which will appear as undeliverables. Typically, this happens when an email address doesn't exist anymore or the relay fully rejects the message. Outlook will file these into the Undeliverable folder for that mailbox on receive. However, these can be prevented when sending via the PoliteMail Server.
In order to prevent this, the Return Path feature can be used. This will redirect the messages to this address, wherein your IT team can manage how they are handled for deletion. For more information on the Return Path feature, please refer to the following article.
To provide this functionality for all messages regardless if the feature is enabled, a custom header with the Return Path info can be applied to all messages from the PoliteMail Server. This will prevent NDRs from being received by any mailbox that sends a message from PoliteMail.
Lastly, there is a statistic for undeliverables in the PoliteMail metrics report. By suppressing these messages, the statistic will not populate, and applying the above solutions should be considered before making suppression a practice.