The answer
The motor is powered but the shredder ring/impeller is mechanically jammed. Thermal overload trips to prevent motor burnout. Fix:
- Unplug unit / turn off breaker
- Clear debris from above with pliers (never hands)
- Insert 1/4" hex Allen wrench into bottom center socket and rotate back and forth to unstick flywheel
- Press red reset button on bottom
- Restore power and test with cold water.
Sources
This answer is drawn from the standards and guidance below. It is general information about how these systems work — not a diagnosis of your property.