Question AR JS Problems and Web AR

Hello,
has anyone else this Problem with AR.js Unity that after I added the files and tried to create an Image Target from AR js I got this error:

ArgumentException: The Object you want to instantiate is null.
UnityEngine.Object.CheckNullArgument (System.Object arg, System.String message) (at <e5b75411c8cd4bfaa9e760be20206f29>:0)
UnityEngine.Object.Instantiate (UnityEngine.Object original, UnityEngine.Vector3 position, UnityEngine.Quaternion rotation) (at <e5b75411c8cd4bfaa9e760be20206f29>:0)
UnityEngine.Object.Instantiate[T] (T original, UnityEngine.Vector3 position, UnityEngine.Quaternion rotation) (at <e5b75411c8cd4bfaa9e760be20206f29>:0)
ARGameObjectCreator.PlaceImageTargetPrefabInScene () (at Assets/ARjs_Unity/ARjs_Unity-master/Editor/ARGameObjectCreator.cs:18)
UnityEditor.GenericMenu:CatchMenu(Object, String[], Int32)


DId anyone else encounter this Problem? I also had it with the version 2020.3.12f1 and the version 2019.4.13f1.
If so than please give me an answer how to fix this.

If not than I ask if there is web-ar support from unity and what is it? Are there also good tutorials for beginners?

 

Got the same error but I made the same thing a year ago and it worked but can’t find that project file