Parameter ‘Walk’ doesn’t exist?

I’m trying to make walk animation. But when I try to change animation idle to walk, ıt doesn’t work. It says ‘Parameter "Walk" doesn’t exist’but I added parameter and script works. I can manually change parameter and it works(walk animation is playing). But when I try to change via script, ıt doesn’t work.

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Here are codes

public class Controller : MonoBehaviour     private Rigidbody rb;  private float xPos;  Vector3 playerMovement;  [SerializeField] Animator anim;      private void Awake() => rb = GetComponent<Rigidbody>();  private void Start() {           xPos = transform.position.x;  }         // Update is called once per frame void Update() {     Move();      }  private void Move() {          float mH = Input.GetAxis("Horizontal");       playerMovement = new Vector3(0, 0, mH);      rb.AddForce(playerMovement * 2f);      anim.SetFloat("Walk", 1);      transform.position = new Vector3(xPos, transform.position.y, transform.position.z);       }