My character cant jump

this is my player Controller script

 using UnityEngine;
 
 [RequireComponent(typeof(Animator))]
 [RequireComponent(typeof(ConfigurableJoint))]
 [RequireComponent(typeof(PlayerMotor))]
 public class PlayerController : MonoBehaviour
 {
 
     [SerializeField]
     private float speed = 5f;
     [SerializeField]
     private float lookSensitivity = 3f;
 
     [SerializeField]
     private float thrusterForce = 1000f;
 
     [Header("Spring settings:")]
     [SerializeField]
     private JointDriveMode jointMode = JointDriveMode.Position;
     [SerializeField]
     private float jointSpring = 20f;
     [SerializeField]
     private float jointMaxForce = 40f;
 
     // Component caching
     private PlayerMotor motor;
     private ConfigurableJoint joint;
     private Animator animator;
 
     void Start()
     {
         motor = GetComponent<PlayerMotor>();
         joint = GetComponent<ConfigurableJoint>();
         animator = GetComponent<Animator>();
 
         SetJointSettings(jointSpring);
     }
 
     void Update()
     {
         //Calculate movement velocity as a 3D vector
         float _xMov = Input.GetAxis("Horizontal");
         float _zMov = Input.GetAxis("Vertical");
 
         Vector3 _movHorizontal = transform.right * _xMov;
         Vector3 _movVertical = transform.forward * _zMov;
 
         // Finale movement vector
         Vector3 _Velocity = (_movHorizontal + _movVertical) * speed;
 
         // Animate movement
         animator.SetFloat("ForwardVelocity", _zMov);
 
         //Apply movement
         motor.Move(_Velocity);
 
         //Calculate rotation as a 3D vector (turning around)
         float _yRot = Input.GetAxisRaw("Mouse X");
 
         Vector3 _rotation = new Vector3(0f, _yRot, 0f) * lookSensitivity;
 
         //Apply rotation
         motor.Rotate(_rotation);
 
         //Calculate camera rotation as a 3D vector (turning around)
         float _xRot = Input.GetAxisRaw("Mouse Y");
 
         float _cameraRotationX = _xRot * lookSensitivity;
 
         //Apply camera rotation
         motor.RotateCamera(_cameraRotationX);
 
         // Calculate the thrusterforce based on player input
         Vector3 _thrusterForce = Vector3.zero;
         
         if (Input.GetButton("Jump"))
         {
             _thrusterForce = Vector3.up * thrusterForce;
             SetJointSettings(0f);
         } else
         {
             SetJointSettings(jointSpring);
         }
 
     }
 
     private void SetJointSettings (float _jointSpring)
     {
         joint.yDrive = new JointDrive {
             mode = jointMode,
             positionSpring = _jointSpring, 
             maximumForce = jointMaxForce
         };
     }
 
 }

And this is my Player Motor Script,

 using UnityEngine;
 
 [RequireComponent(typeof(Rigidbody))]
 public class PlayerMotor : MonoBehaviour
 {
 
     [SerializeField]
     private Camera cam;
 
     private Vector3 velocity = Vector3.zero;
     private Vector3 rotation = Vector3.zero;
     private float cameraRotationX = 0f;
     private float currentCameraRotationX = 0f;
     private Vector3 thrusterForce = Vector3.zero;
 
     [SerializeField]
     private float cameraRotationLimit = 85f;
 
     private Rigidbody rb;
 
     void Start()
     {
         rb = GetComponent<Rigidbody>();
     }
 
     //Gets a movement vector
     public void Move(Vector3 _velocity)
     {
         velocity = _velocity;
     }
 
     //Gets a rotational vector
     public void Rotate(Vector3 _rotation)
     {
         rotation = _rotation;
     }
 
     //Gets a rotational vector for the camera
     public void RotateCamera(float _cameraRotationX)
     {
         cameraRotationX = _cameraRotationX;
     }
 
     //Get a force Vector for our thrusters
     public void ApplyThruster(Vector3 _thrusterForce)
     {
         thrusterForce = _thrusterForce;
     }
 
     // Run every physics iteration
     void FixedUpdate()
     {
         PerformMovement();
         PerformRotation();
     }
 
     //Perform movement based on velocity variable
     void PerformMovement()
     {
         if(velocity != Vector3.zero)
         {
             rb.MovePosition(rb.position + velocity * Time.fixedDeltaTime);
         }
 
         if (thrusterForce != Vector3.zero)
         {
             rb.AddForce(thrusterForce * Time.fixedDeltaTime, ForceMode.Acceleration);
         }
 
     }
 
     //Perform rotation
     void PerformRotation()
     {
         rb.MoveRotation(rb.rotation * Quaternion.Euler (rotation));
         if(cam != null)
         {
             // Set our rotation and clamp it
             currentCameraRotationX -= cameraRotationX;
             currentCameraRotationX = Mathf.Clamp(currentCameraRotationX, -cameraRotationLimit, cameraRotationLimit);
 
             //Apply our rotation to the transform of our camera
             cam.transform.localEulerAngles = new Vector3(currentCameraRotationX, 0f, 0f);
         }
     }
 
 }
 

i am using a brackeys tutorial.