Why are accessories not compatible with Keurig

Why are accessories not compatible with Keurig

I bought a large k-cup and 6 cup carafe mug, and made sure before I purchased them that they were for the right Keurig maker I have! I fill the k-cup with coffee grounds, and place it in the machine. Then I remove the cup tray assembly, and place the craffe mug in its spot. When I try to brew, it tells me that the added accessories are not compatible with the machine?