If an Applications Manager (AM) Standard or RA Agent is in a status of “No_Service”, “Srvc_Down”, or "Running" and it can’t be restarted from the AM Client as indicated in the documentation under Automation Engine/Agent Status Values.
The processes may be able to be started or restarted from the command line by utilizing the stopso and startso commands that are outlined in the Applications Manager Administration Guide, under Starting and Stopping Automation Engine and Agent Processes.
In some cases when an Agent is in any of the above statuses, issuing the following commands on the Agent system as the AM OS user will stop the AgentService processes and allow you to restart the Agent.
Occasionally, the processes fail to stop successfully and cannot be restarted. In those cases, it may be necessary to stop all the AM processes immediately on the Agent system by issuing the following commands:
stopso all –now
CAUTION: Using this command is not recommended in normal situations, but may be necessary in order to ensure all the processes have stopped successfully before attempting to restart the processes using the startso command outlined in the documentation.