You are having issues with Email delivery to the DLP Cloud Service
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You are having issues with Email delivery to the DLP Cloud Service


Article ID: 235230


Updated On:


Data Loss Prevention Cloud Service for Email


You have users reporting that emails are being undelivered due for the below reason.

"Reason: [{LED=421 4.3.0 Tenant Not Assigned. Missing X-DetectorID. Check configuration:};. OutboundProxyTargetIP: OutboundProxyTargetHostName:"


Release : 15.8

Component : DLP Cloud Service for Email


A required configuration is missing from these emails being sent to the service.


The link provided in the error is not up to date, but the details are correctly given: the DLP Cloud Service requires all messages to have a header added in order to be accepted by the service.

This X-header is part of the setup for customers using DLP with O365 in both Forwarding and Reflecting modes, which are covered on these pages:


In each case, go to the section called "Creating a rule that routes emails from Microsoft 365 to your DLP cloud detector".

On-premises Exchange users should instead look for a section called "Routing email to your DLP cloud detector and applying an X-DetectorID message header".


Additional Information

The same details are also given in this guide, on pages 18, 21, and 24:

Symantec_DLP_Cloud_Service_for_Email_Implementation_Guide.pdf (