Check the IP address and port (8000 by default) configuration on the driver and the thermostat.
Make sure the thermostat and the Crestron Home processor are on the same network and they can communicate between them. Make sure there are no network restrictions that filter TCP port 8000.
In order for the thermostat to be controlled by a control system, you will have to enter the installer setup on the thermostat and change it to “Home Automation” mode. Each thermostat has a different way to get into the installer setup and the settings are also laid out different. Please refer to the thermostat manual or contact AprilAire tech support for instructions.