I asked someone about this, and here is the information they provided:
You must set the authentication domain on the individual servers and spawners using the SAS Management Console Server Manager plug-in. For example, for a Workspace server, navigate to:
SASApp > SASApp Logical Workspace Server > SASApp - Workspace Server
In the right-hand pane, right-click on the connection and then select Properties. On the Options tab you will see a selection box for the authentication domain. The process is similar for a Stored Process server, but you will need to set the authentication domain for the connection and any load-balanced connections.
For the object spawner, select the spawner in the Server Manager plug-in, right-click on the operator connection, and then select Properties. The authentication domain can be set on the Options tab. Repeat the process for the port bank connections.
Vince DelGobbo
SAS R&D