Network.Instantiate dont instantiate object

Hi guys,

I have a prefab on the server and on the client, its just a cube with a network view attached to it. When I run the code from the server it works fine on the editor and instantiate the object both on client and server, but when I build the client it doesnt instantiate it. Just on the server.

Can anybody help me ? D:

 public GameObject Defender;
 
     void Update () 
     { 
 
 
 Network.Instantiate(Defender,transform.position,transform.rotation,0);
 
 }