Though the Altiris Agent is connecting to the Notification Server (Basic Inventory, Configuration Updates, Policies, etc) the following error appear in the Agent Logs.
"Description: BaseXmlHttpCallback Exception: System.Net.Sockets.SocketException: No connection could be made because the target machine actively refused it 127.0.0.1:50121"
*Note: The specific port (50121) listed may vary. The most commonly appearing ports are 50121, 50122, 50123, and 50124.
ITMS 7.x - 8.x
A possible cause of these issues is the Altiris Object Host Service failing to bind to any of the ports listed in Settings > All Settings > Site Server Settings > Task Service > Settings >> Task Service Settings.
The Altiris Object Host Service is one of the two main services used by the Client Task Server.
For specifics regarding issues with port bindings for Task Server, see KB 177080.