You have already configured a REST Cloud Detection Server in your Enforce Server console, but you've also purchased a REST Detector to integrate with your REST API and want to add it to Enforce.
Is there a limit on the number of Cloud Detectors you can have in a single console?
Cloud Detection Service for REST
DLP 15.8 or earlier
For DLP 15.8 and prior, there can only be one REST Detector enrolled per Enforce Console - this is by design.
Having 2 of them creates conflicts as the Cloud Service Gateway cannot distinguish between 2 REST Detectors when both are installed in the same Enforce server - so the filters which are responsible for detection will fail to load properly.
If you purchased 2 separate "REST" Cloud Detectors confirm with Technical Support whether both are required:
Having 2 REST Detectors enrolled in the same Enforce Server will cause problems as per this article: CloudSoc Securlets show Sync Failure in DLP when 2 REST Detectors are present (broadcom.com)