remote zensendevent Unauthorized

Hi,

I'm using Zenoss Core 4.2.4 on CentOS 6.5.

A local zensendevent works fine.
A remote zensendevent fails, even when passing the correct username and password with --auth.

I don't see the event in event logs, my guess is that it's blocked ahead, by the daemon handling the traffic of port 8081. Where should I look for this code to debug it

TIA, Charles

Traceback (most recent call last):
File "/opt/gerty/agent/zensendevent", line 264, in
serv.sendEvent(evt)
File "/usr/lib/python2.7/xmlrpclib.py", line 1224, in __call__
return self.__send(self.__name, args)
File "/usr/lib/python2.7/xmlrpclib.py", line 1578, in __request
verbose=self.__verbose
File "/usr/lib/python2.7/xmlrpclib.py", line 1264, in request
return self.single_request(host, handler, request_body, verbose)
File "/usr/lib/python2.7/xmlrpclib.py", line 1297, in single_request
return self.parse_response(response)
File "/usr/lib/python2.7/xmlrpclib.py", line 1473, in parse_response
return u.close()
File "/usr/lib/python2.7/xmlrpclib.py", line 793, in close
raise Fault(**self._stack[0])
xmlrpclib.Fault: