Notifications not being sent failing with error 421 Too many messages for this session

Products

• CA Service Management - Service Desk Manager
• CA Service Desk Manager

Issue/Introduction

The email server has an upper limit of max emails during an SMTP Session and when it hits that limit of maximum emails, the following error appears in NX_ROOT\log\mail_nxd.log:

com.sun.mail.smtp.SMTPSendFailedException: 421 #4.x.2 Too many messages for this session

When the error occurs, SDM moves the email to mails_undeliverable and the notification is not sent to the users.

Environment

SDM 17.x

Cause

This is a product limitation handling 4xx errors

Resolution

SDM 17.4 RU4 (ETA April 2025 - subject to change) will allow retries for the 4xx SMTP errors.

This will require a configuration in the NX.env. You'll need to add NX_EMAIL_RETRY_FOR_TRANSIENT_ERRORS="true" to enable the retry mechanism for all 4xx errors.

Additional Information

List of SMTP server return codes