SMTP Code: "552 4.3.1 Session size exceeds fixed maximum session size"

Products

• Messaging Gateway

Issue/Introduction

Certain messages are rejected by the internal Microsoft Exchange Server during the initial delivery attempt. A review of the Message Audit Logs (MAL) indicates that delivery failed with the following corresponding message:

552 4.3.1 Session size exceeds fixed maximum session size

 

Cause

This SMTP Transaction response is generated because the aggregate size of the SMTP Session itself has exceeded the limit configured on the remote receiver mail server. By default, Messaging Gateway does not impose a limit on the total number of messages delivered over a single SMTP session to internal mail servers.

Resolution

Collaboration with the administrators of the receiving mail server is necessary to determine the required receiving mail server configuration changes or to find alternative delivery workarounds for that destination. The Messaging Gateway is not the source of this issue; therefore, no configuration changes are needed within the Messaging Gateway environment.