Can't add script component "" because the scrrpit class nannot be found

I got the poblem is I build this project .dll to Unity by this tutoial "https://www.youtube.com/watch?v=ha3t40GJ0Wo&ab_channel=EmergentSagas"

And I do the same class name and .cs name arady this is my code

 using TwinCAT.Ads;
 using UnityEngine;
 
 public class ADSpotocol : MonoBehaviour
  {
    private TcAdsClient _tcClient = null;
 
    void Awake()
     {
             _tcClient = new TcAdsClient();
             _tcClient.Connect("1.01", 851);
             if (_tcClient.IsConnected)
             {
                 Debug.Log("Twin CAT ADS port connected");
             }
             else
             {
                 Debug.LogError("ADS Connection failed");
             }
     }
  }

And this this path thai I build

echo f | xcopy "$(TargetPath)" "D:\FOR WORK\WD project\MR project\Final_project\Assets\Plugins" /Y echo f | xcopy "$(TargetDir)$(TargetName).pdb" "D:\FOR WORK\WD project\MR project\Final_project\Assets\Plugins" /Y "C:\Users\HP\Downloads\pdb2mdb.exe" "D:\FOR WORK\WD project\MR project\Final_project\Assets\Plugins\$(T finalproject)"

,

'''`using TwinCAT.Ads; using UnityEngine;

public class ADSpotocol : MonoBehaviour { private TcAdsClient _tcClient = null;

void Awake() { _tcClient = new TcAdsClient(); _tcClient.Connect("1.01", 851); if (_tcClient.IsConnected) { Debug.Log("Twin CAT ADS port connected"); } else { Debug.LogError("ADS Connection failed"); } } }`

I build this project to .dll to unity and use this build event

echo f | xcopy "$(TargetPath)" "D:\FOR WORK\WD project\MR project\Final_project\Assets\Plugins" /Y

echo f | xcopy "$(TargetDir)$(TargetName).pdb" "D:\FOR WORK\WD project\MR project\Final_project\Assets\Plugins" /Y "C:\Users\HP\Downloads\pdb2mdb.exe" "D:\FOR WORK\WD project\MR project\Final_project\Assets\Plugins\$(T finalproject)" When I drac this .cs file it error showing that I can't add this script