Automic Workload Automation

When an agent disconnects, or fails to start, it is recommended to check the latest entry in the Agent's log file (located in the {agent}\temp folder).

One of the many reasons an agent disconnects is due to 

U02000099 Transfer key could not be loaded. Please check, if the KeyStore exists and the agent is authenticated. 

which you should be able to see in the log file.

To get around this:
1) Login on Client 0
2) Open SystemOverview > Agents
3) Right-click the agent and select "Renew Transfer Key"
4) Restart or start the agent

*Some* of the reasons a transfer key may become corrupt and needs to be renewed:
1) server has changed - name, etc
2) IP address has changed

Thank you Christine_Chavez_6412

I think another reason is  when an agent was defined on an AE system(System1). Then, you defined the agent to another AE system(System2) without removing/deleting the agent from System1. Later on, you again try to define the agent back to System1.