Many reasons can lead to the CBA not loaded issue, This document will provide you how does the core detect the agent status.
The LANDESK core server calls cba_anonymous to do an LDping function on the client web service to verify the client prior to executing any functions on the remote agent. You could get the packet trace with wireshark while the core do LDping as below.
The core server(172.29.40.153) calls do an LDping function to the client (172.29.40.190) via TCP port 9595
HTTP response from the client to core.
1,As both the clients and core are using TCP port 9595 to detect the agent status, please check the netstat and tasklist response to ensure it is resident agent only on this port. This could help us verify no any other third party software conflicting with our ports on the client.
If there is no any port conflict issue, please attempt to telnet core via TCP port 9595 to verify if you can reach the core on the affected machine.
2,The LANDESK core server calls cba_anonymous to do an LDping function .So the cba_anonymous account need keep activate status, Please make sure no any domain policy would impact the guest account.
3, Finally you can try to do a uninstall with /forceclean , then reinstall on an affected client, to make sure no any file corrupted.