How do I apply damage to the enemy ai using melee weapon OnControllerColliderhit

I want to take 10 damage amount and using OnControllercolliderhit a melee weapon . I am having some issues . The enemy is not taking any damage . Here is my apply damage script :

using UnityEngine; using System.Collections; using Opsive.ThirdPersonController.Wrappers;

public class ApplyDamage : MonoBehaviour {

LayerMask m_AttackLayer;

Healthbar healthbar;

void Start(){

   healthbar = FindObjectOfType<Healthbar>();
   if (healthbar == null) {
      Debug.LogError("Healthbar class is not found in scene!");

   }

   

}

void OnControllerColliderHit(ControllerColliderHit) { if (hit.gameobject.tag == "Enemy") {
healthbar.SendMessage("I am hit.", health, SendMessageOptions.DontRequireReceiver);

} }

}