UNET. Objects are spawning not properly on the Client

I'm trying to spawn objects and to parent them to another object in the scene. The objects are spawned both on client and host, but the issue is, that parenting is working only on the host.

Setting the parent:

 go.transform.SetParent(GameObject.Find("GameCanvas").transform);

The whole code:

 public override void OnStartServer()
     {
       
             buttonSpawns = GameObject.FindGameObjectsWithTag("ButtonSpawn");
             StartSpawn();
                    
     }
  
  void StartSpawn()
     {
             for (int i = 0; i < numberOfButtons; i++)
             {                
                 SpawnButtons(buttonSpawns[i].transform.position);
             }
     }
     
  void SpawnButtons(Vector3 spawnPos)
     {
         counter++;
 
         GameObject go = GameObject.Instantiate(buttonPrefab, spawnPos, Quaternion.identity) as GameObject;
         go.GetComponent<Button_ID>().buttonID = "Button" + counter;      
              
         go.transform.SetParent(GameObject.Find("GameCanvas").transform);
 
         NetworkServer.Spawn(go);
     }