If security is enabled on the Monitor server, authorizations must be supplied to allow users to work with the models.
In the Admin console under
Security > Monitor Data Security
configuration panels can be found. From there we drill down to the mysterious "root" entry:
and finally get to where we need to be:
Selecting a category of permissions and then clicking either the users or groups buttons allows us to add/remove users/groups from that category of permissions.
Permissions normally need to be set if when you create an Instances widget in Business Space and no models are shown.