The only time the Caps can cause this to happen is when the K-Cup ® Pack is overfilled or packed to tightly with coffee. The water is pushed through the K-Cup ® Pack under pressure. If the coffee in the K-Cup ® Pack is packed so tight that the water can not get through then the water backs up and the machine turns off. The solution is to use less coffee or a less fine grind. The way to test and see if this is what is going on is to run a used K-Cup ® Pack and Cap through your brewer with nothing in it. It should operate normally and make you a nice hot cup of water.