c# - How do I make the iTween plugin work with Unity 2018?

Question

I got iTween from the asset store to Unity 2018. iTween included sample code and sample scenes of the content where the cube object moves left and right. And this worked fine.

I made a new project, made a cube object with the same structure as the sample, attached the sample code. That is this code.

move.cs

enter code here
using UnityEngine;
using System.Collections;

public class MoveSample: MonoBehaviour
{
    void Start () {
        iTween.MoveBy (gameObject, iTween.Hash ("x", 2, "easeType", 
        "easeInOutExpo", "loopType", "pingPong", "delay", .1));
    }
}

Both the object name and the code are the same as the sample project This implementation did not work for some reason and the object did not move left and right.

Does this require something to be done not only in the code but also in scene settings and camera settings?

In the manual, especially iTween calls are not written as required, and there was no need to set up.

Is it a problem unique to Unity 2018?

Please help me.