After upgrading to Symantec Data Loss Prevention (DLP) 15.8, the list of policies shows a warning symbol for several cloud-specific policies.
When drilling in to the policies, the alert reports "This policy has unresolved references, it may not be fully functional. Click here for details."
When clicking on the details it shows CASB Application(s) " are no longer available."
All policies continue to function normally
The connection to the Cloud Service Gateway is good.
Data Loss Prevention 15.8
The common cause on Data Loss Prevention 15.8 is a Contextual Attribute rule.
When creating a new cloud policy with only the Contextual Attribute rule, a cloud policy immediately shows an alert icon.
There is a similar issue that is not resolved with the fix given above. For a description of that issue, please see DLP Cloud Policies have a Warning Alert about unresolved references (broadcom.com).