How to fix this animator is not playing an animatorcontroller?

How do I fix this warning sign that keeps popping up in Unity.

My code is

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class Fighter_Player : MonoBehaviour {
public enum PlayerType
{
HUMAN, AI
}

 public static float MAX_HEALTH = 100F;

 public float healt = MAX_HEALTH;
 public string fighterName;
 public Fighter_Player oponent;

 public PlayerType player;

 protected Animator Player;
 private Rigidbody myBody;

 // Use this for initialization
 void Start () {
     myBody = GetComponent<Rigidbody> ();
     Player = GetComponent<Animator> ();
 }

 public void UpdateHumanInput () {
     if (Input.GetAxis ("Horizontal") > 0.1) {
         Player.SetBool ("Walk_Forward", true);
     } else {
         Player.SetBool ("Walk_Forward", false);
     }

     if (Input.GetAxis ("Horizontal") < -0.1) {
         Player.SetBool ("Walk_Backward", true);
     } else {
         Player.SetBool ("Walk_Backward", false);
     }

     if (Input.GetAxis ("Vertical") < -0.1) {
         Player.SetBool ("Duck", true);
     } else {
         Player.SetBool ("Duck", false);
     }

     if (Input.GetKeyDown (KeyCode.F)) {
         Player.SetTrigger ("Punch_Mid");
     }

     if (Input.GetKeyDown (KeyCode.G)) {
         Player.SetTrigger ("Special_Move");
     }
 }


 // Update is called once per frame
 void Update () {
     Player.SetFloat ("health", healtPercent);

     if (oponent != null) {
         Player.SetFloat ("oponent_health", oponent.healtPercent);
     } else {
         Player.SetFloat ("oponent_health", 1);
     }

     if (player == PlayerType.HUMAN) {
         UpdateHumanInput ();
     }
 }

 public float healtPercent {
     get {
         return healt / MAX_HEALTH;
     }
 }

 public Rigidbody body {
     get {
         return this.myBody;
     }
 }

}

I also would like to know how to program an AI fighter. I have been following this guy for my code and AI Creating a Street Fighter game with Unity - 15 Implementing AI with a state machine for fighting - YouTube

but when I type in the code for the AI, the controller stopped working and all I could do was walk forward and eventually got to the point where I couldn’t move at all.