ID Monitoring and Denylisting

The DCS monitors the IDs it receives and adds those that are being sent at an unusually high rate over a short period of time to a deny list.


To protect the Audience Manager infrastructure against malicious activity, the DCS uses an advanced algorithm to monitor the IDs it receives. These can be Data Provider Unique User IDs (CRM IDs), Audience Manager Unique User IDs (AAM UUIDs), or Experience Cloud IDs (ECIDs). See Index of IDs in Audience Manager for detailed explanations of the IDs supported by Audience Manager.

The DCS monitors the frequency at which it receives these IDs to detect potential malicious activity. When the DCS detects an unusually large amount of DCS requests for any given ID in a short amount of time, that ID is added to a deny list.

Error Codes

You can identify IDs added to a deny list by the error codes received from the DCS. The error codes that you may receive are:

  • 303: Blocked customer ID;
  • 306: Blocked declared device ID;
  • 307: Blocked profile operation for ID.

See DCS Error Codes, Messages, and Examples for details on the error codes that you may receive.

Removing IDs from deny lists

IDs that have been added to deny lists should not be used in any future requests, since they will lead to incorrect data reporting. The DCS does not support the removal of IDs from deny lists.

Impact on ID Synchronization

DCS calls can include one or multiple types of IDs. Calls containing a single ID are completely disregarded if that ID is added to a deny list, and no ID synchronization occurs in this situation.

When a multiple ID call also includes a denylisted ID, the DCS disregards the denied ID and only uses the remaining, allowed IDs for synchronization.

Causes and Fixes for ID Denylisting

The most frequent cause of IDs being added to deny lists is the incorrect integration between customer infrastructure and Audience Manager. When you identify a denylisted ID, make sure to thoroughly review your Audience Manager integrations. See Implementation and Integration Guides for detailed explanations of how you should configure Audience Manager to work with other Experience Cloud solutions or external systems.

Another frequent cause of IDs being added to deny lists are indexing bots (web crawlers), which generally cause increases in traffic, leading to the same IDs being sent to the DCS multiple times. If you identify indexing bots as the reason for IDs being added to deny lists, you should restrict bot access to your website.

If you have a hard time identifying integration issues, don’t hesitate to contact Customer Support. Prior to opening a support request, make sure to keep the .har HTTP archive of your browser ready. This archive helps the support team identify why the ID was added to a deny list.