Toilets can break for a number of reasons, some of which are bizarre and due to outside forces. But the most common cause of toilets not flushing have to do with the lift arm and its attachment. If the handle feels loose, it may need to be tightened to the lift arm inside the basin. The lift arm itself can break from rust or just bending from being battered. The chain linking the plug might detach or be too lose. All are easy fixes you should check if your toilet won’t flush.