The agent architecture requires some prerequisites.
Make sure that Main JobScheduler can communicate with the Agent JobScheduler and vice versa.
For this, edit the ./config/scheduler.xml of the Main JobScheduler:
...
<[http://www.sos-berlin.com/doc/en/scheduler.doc/xml/security.xml security] ignore_unknown_hosts="yes">
...
<[http://www.sos-berlin.com/doc/en/scheduler.doc/xml/allowed_host.xml allowed_host] host="[host or IP of the Agent JobScheduler]" level="all"/>
</security>
...
and edit the ./config/scheduler.xml of the Agent JobScheduler:
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<[http://www.sos-berlin.com/doc/en/scheduler.doc/xml/security.xml security] ignore_unknown_hosts="yes">
...
<[http://www.sos-berlin.com/doc/en/scheduler.doc/xml/allowed_host.xml allowed_host] host="[host or IP of the Main JobScheduler]" level="all"/>
</security>
...
Make sure that no firewall restricts the communication.