Why can't i jump? I have "GROUNDED" and "jump" in console, but my gameObject doesn't jump, please help

Questions & Answers
1 
using System.Collections.Generic;
using UnityEngine;

public class CatScript : MonoBehaviour
{
    private Rigidbody2D body;
    private float moveSpeed = 2.0f;
    private bool _isGrounded;
    public float JumpForce = 2.5f;
    private bool facingRight = true;
    // Start is called before the first frame update
    void Start()
    {
        body = GetComponent<Rigidbody2D>();
        body.freezeRotation = true;
    }

    // Update is called once per frame
    void Update()
    {
        float h = Input.GetAxisRaw("Horizontal");
        body.velocity = new Vector2(h * moveSpeed, 0);

        if (Input.GetKey(KeyCode.Space) && _isGrounded)

        {
            Debug.Log("jump");
            body.velocity = new Vector2(body.velocity.x,JumpForce);
            _isGrounded = false;
        }

        if (h < 0 && facingRight)
        {
            flip();
        }
        if (h > 0 && !facingRight)
        {
            flip();
        }
    }
    private void OnCollisionEnter2D(Collision2D collision)
    {
        Debug.Log("GROUNDED"); 
        if (collision.gameObject.tag == "Ground")
        {
            _isGrounded = true;
        }
    }
    private void flip()
    {
        facingRight = !facingRight;
        transform.Rotate(0, 180, 0);
    }
}
2 
using System.Collections.Generic;
using UnityEngine;

public class CatScript : MonoBehaviour
{
    private Rigidbody2D body;
    private float moveSpeed = 2.0f;
    private bool _isGrounded;
    public float JumpForce = 2.5f;
    private bool facingRight = true;

    // Start is called before the first frame update
    void Start()
    {
        body = GetComponent<Rigidbody2D>();
        body.freezeRotation = true;
    }

    // Update is called once per frame
    void Update()
    {
        float h = Input.GetAxisRaw("Horizontal");
        body.velocity = new Vector2(h * moveSpeed, body.velocity.y); // Preserve the current y velocity.

        if (Input.GetKeyDown(KeyCode.Space) && _isGrounded)
        {
            Debug.Log("Jump");
            body.AddForce(new Vector2(0, JumpForce), ForceMode2D.Impulse);
            _isGrounded = false;
        }

        if (h < 0 && facingRight)
        {
            flip();
        }
        if (h > 0 && !facingRight)
        {
            flip();
        }
    }

    private void OnCollisionEnter2D(Collision2D collision)
    {
        Debug.Log("GROUNDED");
        if (collision.gameObject.tag == "Ground")
        {
            _isGrounded = true;
        }
    }

    private void flip()
    {
        facingRight = !facingRight;
        transform.Rotate(0, 180, 0);
    }
}

try it