DIAGNOSIS This is almost always an assembly error—the main power cable isn't fully seated or a safety interlock isn't engaged.
FIX Check the main power connection at the back of the grill. The plug goes into a socket, THEN you must rotate the locking collar clockwise until it clicks and locks. This step is constantly missed.
IF THAT DIDN'T WORK Verify the hopper lid is completely closed and latched. There's a safety switch that prevents operation if the hopper is open. Also, check your household GFCI outlet—it may have tripped. Test with another appliance.
HEADS UP During assembly, it's easy to pinch or disconnect the thin wiring for the controller behind the hopper. If the above steps fail, you may need to partially disassemble to check those connections.