Generally, an application has to be published before it can be accessible to users. Radius applications have to be published on Radius servers.
To publish an application, select "Authentication | Agents", find the application and click its context menu, then select "Agents" from the menu:
This will bring up a list of agents:
Select the Radius server(s) on which you want to publish the application. An application can be publish on one or many servers.