I recommend checking the tension on the belt and adjusting it if necessary. The image below shows an excerpt from your owner's manual that describes how to check and adjust the belt tension.
If this does not help, unplug the bike and check the wiring connections between the display console and the resistance motor. If the wiring connections are okay, then you could have a failed resistance motor or a failed console control.
I recommend having a service technician diagnose and repair this type of problem.