Unable to sync training route made in Garmin Connect to handheld Garmin66st.

I created a new training route using the Garmin Connect web site.  The route transferred without issues to my IPhone8. When I try and sync the route to my handheld (Garmin66st), I get a message stating “Device not Compatible .”  I’ve tried Bluetooth, WiFi, and Computer with USB cable.  Software is current on both devices.  Any suggestions would be appreciated.  Thanks...