Messages with a large number of recipients are delayed during sending in Outlook

Products

• Data Loss Prevention Endpoint Prevent

Issue/Introduction

You are running Data Loss Prevention (DLP) Endpoint Prevent with the Outlook plug-in enabled. Users are reporting messages with a large number of recipients are taking longer than usual to send.

Cause

The delay occurs due to the need for DLP to enumerate each recipient against the DLP policy set. 

Resolution

This is expected behavior.

It is recommended to create a distribution list instead to work around this issue. Note: Users should be instructed to not expand the distribution list as this will cause the issue as well.