bpms rest api does not let me get process variables

I am trying to get the variables of a process instance in a bpms6 server

I am using this url

http://localhost:8080/business-central/rest/runtime/my.package:Process:1.0.0/process/instance/1/variables, but the result is nothing useful:

SUCCESS
/business-central/rest/runtime/com.ec.mutualista:Promocion:1.0.0/process/instance/33/variables

any patch available ??