Engineering indicated the KMS service won't return a more descriptive error due to possible cross org exposure. For example, if the Cisco org was in a external customer space and participated in a conversation (which would return events for the external space), and the external customer's HDS site was having trouble, there are privacy/security concerns if a more detailed error is returned. Essentially Cisco, in this example, would then know the external customer had encryption issues.
That clearly poses a bit of a "self service" situation, where it's not as easy to determine root cause of a problem, but that's the reasoning behind having a less helpful error in this particular case. This has been submitted as a feature request and is currently in the Backlog.
