Error

So I followed a tutorial and changed a bunch of code and everytime i run the code i get this error:
ArgumentException: Input Axis mouse X is not setup.
To change the input settings use: Edit -> Settings -> Input

Can someone tell me where am i making a mistake and how to fix it?
Code:
public class movement : MonoBehaviour
{
[SerializeField] private float mouseSensitivity;

private float xAxisClamp;

void Start()
{
xAxisClamp = 0.0f;
Cursor.visible = false;
Cursor.lockState = CursorLockMode.Locked;
}

private void Update()
{
float mouseX = Input.GetAxis("MouseX") * mouseSensitivity * Time.deltaTime;
float mouseY = Input.GetAxis("MouseY") * mouseSensitivity * Time.deltaTime;
xAxisClamp += mouseY;
transform.Rotate(-transform.right * mouseY);
void ClampXAxisRotationToValue(float value)
{
Vector3 eulerRotation = transform.eulerAngles;
eulerRotation.x = value;
transform.eulerAngles = eulerRotation;
}
}
}