How do I know if another user in my environment is busy on a call or is idle?through XSI-ACTIONS?

Hi,I try to subscribe to XSI events with this uri:http://broadsoftsandboxxsp.cisco.com/com.broadsoft.xsi-events/v2.0/user/u9736722461@broadsoftlab.combut in response I receive that the expiration is 0 and I can no longer receive any more events.Why i...