Question why do i have this error

NullReferenceException: Object reference not set to an instance of an object
UnityEditor.PropertyHandler.IsArrayReorderable (UnityEditor.SerializedProperty property) (at <11d97693183d4a6bb35c29ae7882c66b>:0)
UnityEditor.PropertyHandler.UseReorderabelListControl (UnityEditor.SerializedProperty property) (at <11d97693183d4a6bb35c29ae7882c66b>:0)
UnityEditor.PropertyHandler.GetHeight (UnityEditor.SerializedProperty property, UnityEngine.GUIContent label, System.Boolean includeChildren) (at

 

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

public class jump : MonoBehaviour
{
public float height;

bool grounded;

Rigidbody2D myBody;
Animator myAnim;

// Start is called before the first frame update
void Start()
{
myBody = GetComponent<Rigidbody2D>();
myAnim = GetComponent<Animator>();
}

// Update is called once per frame
void FixedUpdate()
{
if (Input.GetKey(KeyCode.UpArrow))
{
if (grounded)
{
grounded = false;
myBody.velocity = new Vector2(myBody.velocity.x, height);
}
}
}

void OnCollisionEnter2D(Collision2D other)
{
if(other.gameObject.tag == "ground")
{
grounded = true;
}
}
}

 

this is my script

 

From Nerdish to English: component don't exist so I can't use it. Check if you have Rigidbody2D on same game object like script.