Messages in the Messaging Gateway delivery queue are not delivered

Products

• Messaging Gateway

Issue/Introduction

Messages in the Symantec Messaging Gateway (SMG) delivery queue are not delivered to their intended mail server.

Cause

Messages can accumulate in the delivery queue when the SMG Mail Transfer Agent (MTA) is unable to successfully deliver messages to their intended destination.

Resolution

Messages can accumulate in the delivery queue for a number of reasons, including the following:

•  SMTP Code: "421 4.4.0 [internal] no MXs for this domain could be reached at this time" and emails are stuck in the delivery queue
• SMTP Code: "450 4.3.2 try again later"
•  SMTP Code: "450 4.4.1 [Internal] Connection timed out"
•  SMTP Code: "450 4.7.1: Helo command rejected: Host not found" and outbound messages are not delivered
•  SMTP Code: "552 4.3.1 Session size exceeds fixed maximum session size"

In general, when delivering mail from Messaging Gateway, there may be some undeliverable messages in the delivery queue. Some messages may not be properly addressed, or the destination mail server is not accessible.

View the delivery queue at Status > Message Queues > Queue: Delivery, which provides more detailed information as to why messages have been queued. Look under the "Error" column of the queue listing.

For more information, search the Symantec Knowledge Base for the specific status message or SMTP code.