Why Won't it jump?

Player won't jump. Unity 5. using UnityEngine; using System.Collections;

 public class SimplePlatformController : 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;
     }
 }