Debug business logic requiring logged in user

I have logged in via the REST console to get a user-token in order to debug a service I just deployed (to Debug). When I use that user-token however and call Backendless.UserService.CurrentUser() in the service it always returns null. How can I get a valid user-token that I can use to debug the service? Thanks

To get the identity (objectId) of the user that performed the API call which triggered a service invocation, use the following API:

com.backendless.servercode.InvocationContext.getUserId()

Regards,
Mark