It should be straight forward as long as you're using an Admistrator user from the org within which the workspaces are located.
Are you using an Org Admin user to list the workspaces? If yes, then please create a ticket for this (email to devsupport@webex.com) with the user email and trackingId for the request that was made. Also share the request, if you're adding values such as orgId or other values.