Apologies for the slow response, it looks like this issue was corrected through a case. In case someone else encounters this issues, the fix was to change the admin password in the console then re-installed the agent on all computers.
yes I already discover this by Myself, once replace the password (actually I just re-write the same one.... and communication between server and workstation start to work normally)
But I noticed that I also needed to update the Ivanti scheduler on each workstation...... I had to this one by one. (Right click on the station and select scheduler)
Because I use to see all computer in the <<Scheduled Console Tasks>> and cannot see anything meaning it is all blank.
Let me know if there is another way to Update scheduler on all workstation in a better way.
You shouldn't have to manual upgrade schedule on the targets. The scheduler should upgrade or re-install itself during the deployment attempt against the machine. FYI: The scheduler isn't used for agent based scans or deployments. It's only used for agentless tasks.