JON Agent fails to perform plug-in update at startup due to: Command failed to be authenticated

Issue

• Agent plug-in download fails
• new plugins installed into JON are not downloaded by the agent at startup
• Agent seems to ignore rhq.agent.update-plugins-at-startup

• Agent log contains the following warning within a minute of startup:

  WARN  [RHQ Server Polling Thread] (org.rhq.enterprise.agent.AgentMain)- {AgentMain.plugin-update-failure}Failed to update the plugins.. Cause: org.rhq.enterprise.communications.command.server.AuthenticationException: Command failed to be authenticated!  This command will be ignored and not processed: Command: type=[remotepojo]; cmd-in-response=[false]; config=[{rhq.agent-name=localhost.localdomain, rhq.externalizable-strategy=AGENT, rhq.send-throttle=true}]; params=[{invocation=NameBasedInvocation[getLatestPlugins], targetInterfaceName=org.rhq.core.clientapi.server.core.CoreServerService}]