Jump Script Not Working

Hi, I'm new to unity and am currently having trouble getting my character to jump. I have a jump script in my player controller but when I click space to jump nothing happens. I have the jump action mapped to space in my Input Actions. Here is the code:

 public class ThirdPersonScript : MonoBehaviour
 {
     public CharacterController controller;
     public Transform cam;
 
     public float speed = 6;
     public float gravity = -9.81f;
     public float jumpHeight = 3;
     Vector3 velocity;
     bool isGrounded;
 
     public Transform groundCheck;
     public float groundDistance = 0.4f;
     public LayerMask groundMask;
 
     float turnSmoothVelocity;
     public float turnSmoothTime = 0.1f;
 
     //Reference to InputActions script
     private PlayerActionControls playerActionControls;
 
     //Reference to animator component
     private Animator animator;
 
     //Called once at start
     private void Awake()
     {
         playerActionControls = new PlayerActionControls();
         animator = GetComponent<Animator>();
     }
 
     private void OnEnable()
     {
         playerActionControls.Enable();
     }
 
     private void OnDisable()
     {
         playerActionControls.Disable();
     }
 
     // Update is called once per frame
     void Update()
     {
         Move();
         Jump();
     }
 
     private void Jump()
     {
         isGrounded = Physics.CheckSphere(groundCheck.position, groundDistance, groundMask);
 
         if (isGrounded && velocity.y < 0)
         {
             velocity.y = -2f;
         }
 
         if (Input.GetButtonDown("Jump") && isGrounded)
         {
             velocity.y = Mathf.Sqrt(jumpHeight * -2 * gravity);
         }
     }
 
     private void Move()
     {
         //gravity
         velocity.y += gravity * Time.deltaTime;
         controller.Move(velocity * Time.deltaTime);
 
         //walk
         float horizontal = Input.GetAxisRaw("Horizontal");
         float vertical = Input.GetAxisRaw("Vertical");
 
         //Read the movement value
         Vector2 movementInput = playerActionControls.Player.Move.ReadValue<Vector2>();
         //Move the player
         Vector3 direction = new Vector3(horizontal, 0f, vertical).normalized;
 
         if (direction.magnitude >= 0.1f)
         {
             float targetAngle = Mathf.Atan2(direction.x, direction.z) * Mathf.Rad2Deg + cam.eulerAngles.y;
             float angle = Mathf.SmoothDampAngle(transform.eulerAngles.y, targetAngle, ref turnSmoothVelocity, turnSmoothTime);
             transform.rotation = Quaternion.Euler(0f, angle, 0f);
             Vector3 moveDir = Quaternion.Euler(0f, targetAngle, 0f) * Vector3.forward;
             controller.Move(moveDir.normalized * speed * Time.deltaTime);
         }
 
         //Setting "Run" bool in animator
         if (Mathf.Approximately(movementInput.sqrMagnitude, 0) == false) animator.SetBool("Run", true);
         else animator.SetBool("Run", false);
     }
 }

Thanks.