fps jump Brackeys

I was following Brackeys but the jump is broken how can I fix it? is it broken? are there typos?
im new to coding if you cant tell

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

 public class playerMovement : MonoBehaviour

{

 public CharacterController controller;

 public float speed = 12f;
 public float gravity = -9.81f;
 public float jumpHight = 3f;

 public Transform groundCheck;
 public float groundDistance = 0.4f;
 public LayerMask groundMask;

 public float verticalVelocity;

 Vector3 velocity;
 bool isGrounded;

   


 // Start is called before the first frame update
 void Start()
 {
     
 }

 // Update is called once per frame
 void Update()
 {
     isGrounded = Physics.CheckSphere(groundCheck.position, groundDistance, groundMask);

     if(isGrounded && velocity.y < 0)
     {
         velocity.y = -2f;
     }

     float x = Input.GetAxis("Horizontal");
     float z = Input.GetAxis("Vertical");
     
     Vector3 move = transform.right * x + transform.forward * z;

     controller.Move(move * speed * Time.deltaTime);

     if(Input.GetButtonDown("Jump") && isGrounded)
     {
         velocity.y = Mathf.Sqrt(jumpHight * -2f * gravity);
     }



     velocity.y += gravity * Time.deltaTime;

     controller.Move(velocity * Time.deltaTime);

 }
 }

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