SMTP Status: 450 4.7.1 error: too much mail from [IP address]

Products

• Messaging Gateway

Issue/Introduction

Email messages to one or more domains a accumulating in the Messaging Gateway delivery queue with the SMTP status:

450 4.7.1 error: too much mail from 10.20.30.40

The IP address displayed in the SMTP response may be the IP address of the Messaging Gateway but not necessarily the IP of the Messaging Gateway

Cause

The destination email server is temporarily deferring delivery of the email message due to a local policy configuration. In this case, the destination email server may be rate limiting email delivery.

Resolution

This does not represent a problem with Messaging Gateway as the destination email system is making the decision to temporarily not accept email delivery. Since this is a temporary deferral, the email message will be queued on the Messaging Gateway and delivery retried based on the usual queue processing schedule until either the destination mail server accepts the message or it is bounced after being in the queue for a week.