My 2D character doesnt Jump

Hey guys. I’ve been using Unity for a long time now, but i havent met an issue like this yet.

My character can’t jump and i dont know why. The Debug works, he just doesnt want to jump

public float Horizontal;
public float speed = 10;
public Rigidbody2D rb;
public bool isGrounded;
public float JumpHeight = 80f;

void Update()
{
   Horizontal = Input.GetAxisRaw("Horizontal");
   if (Input.GetKeyDown(KeyCode.Space) && isGrounded)
   {
       rb.AddForce(new Vector2(0, JumpHeight), ForceMode2D.Impulse);
       Debug.Log("MOCSKOS KURVA ANYÁDAT");
   }
}

void FixedUpdate()
{
   rb.velocity = new Vector2(Horizontal * speed, 0);
}