my player does the animation on the floor as if he had to jump but walking makes the animation stop I think it's the groundcheck that does not work. I have bad English it was in the translator.

Questions & Answers
1

sing UnityEngine;
using System.Collections;

public class Player : MonoBehaviour
{

[HideInInspector] public bool facingRight = true;
[HideInInspector] public bool jump = false;
public float moveForce = 365f;
public float maxSpeed = 5f;
public float jumpForce = 1000f;
public Transform groundCheck;

private bool grounded = false;
private Animator anim;
private Rigidbody2D rb2d;

// Use this for initialization
void Awake()
{
    anim = GetComponent<Animator>();
    rb2d = GetComponent<Rigidbody2D>();
}

// Update is called once per frame
void Update()
{
    grounded = Physics2D.Linecast(transform.position, groundCheck.position, 1 << LayerMask.NameToLayer("Ground"));

    if (Input.GetButtonDown("Jump") && grounded)
    {
        jump = true;
    }
}

void FixedUpdate()
{
    float h = Input.GetAxis("Horizontal");

    anim.SetFloat("Speed", Mathf.Abs(h));

    if (h * rb2d.velocity.x < maxSpeed)
        rb2d.AddForce(Vector2.right * h * moveForce);

    if (Mathf.Abs(rb2d.velocity.x) > maxSpeed)
        rb2d.velocity = new Vector2(Mathf.Sign(rb2d.velocity.x) * maxSpeed, rb2d.velocity.y);

    if (h > 0 && !facingRight)
        Flip();
    else if (h < 0 && facingRight)
        Flip();

    if (jump)
    {
        anim.SetTrigger("Jump");
        rb2d.AddForce(new Vector2(0f, jumpForce));
        jump = false;
    }
}

void Flip()
{
    facingRight = !facingRight;
    Vector3 theScale = transform.localScale;
    theScale.x *= -1;
    transform.localScale = theScale;
}

}

2

You don’t define what ‘groundCheck’ is, so Unity can’t execute line 23.

Add

groundCheck = transform.Find("groundCheck");

to your Awake method.

This should solve your issue.