UE launch command template is :: …/…/…/Samples/Showcases/Mobile/Mobile.uproject -filehostip=###.###.###.### -nosound -streaming. It seems like it will not register new parameter as you added . If you can launch your game with your customization arguments in development mode. It seems like your parse code has been forbid run when you shipping your game. So you just need to adjust the place of your code.