ERROR: Call "ServiceDirectory.QueryServiceEndpointList" for object "ServiceDirectory" on vCenter Server

Not sure what causes this error.  Google search returned very few hits.  The only solutions proposed:

• Disable Routing and Remote Access service.
• Restart vCenter Server service.

The Routing and Remote Access service was already disabled so I just restarted the vCenter Server service and the error went away.

I'll update this post if a root cause ever presents itself.