The warning message is just a warning and it will not prevent your game from running, but it’s good to know what is causing it and how to fix it for better performance and functionality of your game.
It’s hard for me to tell you how to properly resolve the warning, unless I know the code that controls the player controller. It seems like you are trying to enable input for a specific player controller on a LevelScript actor (such as a Blueprint) but it will be enabled for all player controllers instead.