First Person Controller not working

I'm making a first person shooter, and whenever I add a gun as a child to the camera of the First Person Controller, I can't move when I press play. I can look around, but no movement. Is there a reason why this isn't working?

Sounds like your gun is colliding with your player causing physics confusion, and stoping the CharacterController from moving.

Try removing the collider, and replacing it whit some simple-colliders and making sure that those colliders do NOT collide with the CharacterController.