is the cast node being executed? if it is then check to make sure that it is running true, if its false then you need to set your game instance in the project settings under maps and modes. if the cast isnt being executed then you need to look farther back to make sure that the actor is set to receive input from the player, check to be sure the function you have is setup properly, and make sure that everything is executed at each step (make sure the branch is set to true).