Self-created animation is not executed correctly

I have created an animation with the sequencer. The character is supposed to make a simple stomping movement. He squats slightly, lifts his left leg and stamps it on the floor. I also have this animation sequence as an animation montage and in both cases you can see in the preview that his leg is lifted. I call up this montage by pressing a button. In the game, however, only his arms move and his legs hardly move at all and they don’t leave the ground. What have I forgotten to set?