Silent monitor - Operation Not Allowed exception

Q. When I try to do a silent monitor on agent's active call,  the below error get's thrown.

com.cisco.jtapi.PlatformExceptionImpl: Operation not allowed

May I know from where we can get the detailed information about why the operation is not allowed? Couldn't find anything useful in call manager's /var/log/active/cm/trace/cti/sdl even after enabling all trace levels in serviceability page of CM.

The request is sent as below from a test program.

  CiscoCall monitorCall = (CiscoCall) provider.createCall();

  monitorCall.startMonitor(

   supervisorTerminal,   // Supervisor Phone MAC

   supAddr,       // Supervisor DN

   agentTerminalConnection,

    CiscoCall.SILENT_MONITOR,

    CiscoCall.PLAYTONE_NOLOCAL_OR_REMOTE);

The full program is attached.

A. This is typical seen if application/end user doesn't have 'Standard CTI Allow Call Monitoring' role assigned.

Check if jtapiuser has this role. Add if needed and retry.