The reason why it’s not work as I’ve all ready said is the controller in which your getting, “Index 0”. Regardless of who runs the command it will always try to get the very first controller. If your the second person to join the game your controller would be 1. If your the 10th person to join your controller would be 9.
Having said that I think I may have got a work around for you. Place a variable in your player controller that’s a player controller and set it to self. Then inside your character “Get Controller” and then cast to your player controller, from that you can get your variable you set which should be the reference to self. 
