If the Administration Agent is invoked using an account that does not belong to the Administrators group, the following events occur:

• Occurrence timing
  When Cosminexus Management Server - Administration Agent is invoked from a Windows service or when the adminagentctl start command is executed
  
• Events
  An attempt to invoke the Administration Agent fails. Also, "KEOS21108-E The administration agent could not be started. (detail = The logon user is not using a local system account, or does not belong to the Administrators group)" is output to the event log.
  

As an action, use the account for logging on to Cosminexus Management Server - Administration Agent from the Windows service as a local system account, or change the account to one belonging to the Administrators group.