Colliders doesn t collide with CharacterController

Hi, i have a character controller and a cube in my scene what i am trying to do is playing animation that was attached on the cube when the player collide with it

this is my script

 function OnCollisionEnter(hit:Collision){
   if(hit.gameObject,tag=="Player")
    animation.Play("rotate");
 }
 this script is attached to the cube but when it collide nothing happen may someone tell me what's wrong?? thanks