some causes of this problem:
- port filtering in your network, on 16992/16993, that also can be the Windows Firewall blocking this connection on client side - you can test for this case, trying to close a telnet connection in these ports remotely;
- You also may be missing the LMS component on client side - this services can be downloaded from OEM website and while OS is running, this service is responsible to redirect connection for this ports to ME - that is the reason, that works while machine is powered down and doesn't while powered on.
Best Regards!
-Bruno Domingues