web view is not working

I added the webview plugin to the existing project, but the webview does not open.
did i do something wrong?

unity version 2020.3.10f1

dist-> unity-webview.unitypackage Import

`using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Networking;

public class WebView : MonoBehaviour
{
WebViewObject webViewObject;

public void Event_WebView(string URL, GameObject gameObject)
{
    StartCoroutine(webview(URL, gameObject));
}

private IEnumerator webview(string URL, GameObject gameObject)
{
    gameObject.SetActive(true);
    webViewObject = gameObject.AddComponent<WebViewObject>();
    webViewObject.Init(
        ld: (msg) =>
        {
            webViewObject.EvaluateJS(@"Unity.call('ua=' + navigator.userAgent)");
        },
        enableWKWebView: true);
    webViewObject.SetMargins(0, 195, 0, 0);       // 화면 여백
    webViewObject.SetVisibility(true);          // 보일껀지 말껀지

#if !UNITY_WEBPLAYER && !UNITY_WEBGL
if (URL.StartsWith("http"))
{
webViewObject.LoadURL(URL.Replace(" ", "%20"));
Debug.Log("SEUL VALUE CHECK : " + URL.Replace(" ", "%20"));
}
else
{
var exts = new string[]{
".jpg",
".js",
".html" // should be last
};
foreach (var ext in exts)
{
var url = URL.Replace(".html", ext);
var src = System.IO.Path.Combine(Application.streamingAssetsPath, url);
var dst = System.IO.Path.Combine(Application.persistentDataPath, url);
byte[] result = null;
if (src.Contains("://"))
{ // for Android
var unityWebRequest = UnityWebRequest.Get(src);
yield return unityWebRequest.SendWebRequest();
result = unityWebRequest.downloadHandler.data;
}
else
{
result = System.IO.File.ReadAllBytes(src);
}
System.IO.File.WriteAllBytes(dst, result);
if (ext == ".html")
{
webViewObject.LoadURL("file://" + dst.Replace(" ", "%20"));
break;
}
}
}
#endif

    yield break;
}

}
`

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

public class TEST : MonoBehaviour
{
public WebView webview;

public GameObject TEMP;

private string URL = "https://www.naver.com/";

// Start is called before the first frame update
void Start()
{
    TEMP.SetActive(true);
    webview.Event_WebView(URL, TEMP);
}




public void Button_Exit()
{
    if (TEMP.GetComponent<WebViewObject>() != null)
    {
        Destroy(TEMP.GetComponent<WebViewObject>());
        TEMP.SetActive(false);
    }
}

}
`
I wrote the code as above, After adding 'UNITYWEBVIEW_ANDROID_USES_CLEARTEXT_TRAFFIC' built.

The screen is the same as the default screen,
No problems are logged in logcat.

How do i do?

Start by reproducing the issue with Unity 2020.3.10f1 and the imported dist/unity-webview.unitypackage, using the WebView and TEST entry points shown in the report. Inspect WebViewObject initialization and the Android logcat output; the issue is resolved when the supplied webview opens or the missing setup requirement is documented.