I'm not familiar your specific model, but - probably worth crawling underneath the trailer to take a look and check a couple of easy fixes before you take it to the dealer. The slide motors usually have an inline fuse in the wire going to the motor. I doubt this is the issue though if you can hear the motor when you push the button.
The other possibility is a shear pin. Not sure if your setup has one or exactly where to find it, but there may be a pin connecting the motor shaft to the slide mechanism. It is intentionally the weak point, so if something binds or jams that breaks rather than more expensive parts like the motor itself.
I would start with verifying that you have power to the motor, and if so, try to trace through and see why the slide isn't actually moving.
2005 F-150 FX4
2013 Rockwood Roo 23 IKSS