How to spawn gameobject from host to all clients

Questions & Answers
1

i want a object to spawn every few sec,on all my clients, i have a gameobject in which i have attacted this script and added network identity. (unticked both) and the spawning object has network identiy (both unticked) aswell as registered to network manager.but everytime it spawns i get following error.

NullReferenceException: Object reference not set to an instance of an object
UnityEngine.Networking.NetworkServer.GetNetworkIdentity (UnityEngine.GameObject go, UnityEngine.Networking.NetworkIdentity& view) (at C:/buildslave/unity/build/Extensions/Networking/Runtime/NetworkServer.cs:1096)
UnityEngine.Networking.NetworkServer.SpawnObject (UnityEngine.GameObject obj) (at C:/buildslave/unity/build/Extensions/Networking/Runtime/NetworkServer.cs:1302)
UnityEngine.Networking.NetworkServer.Spawn (UnityEngine.GameObject obj) (at C:/buildslave/unity/build/Extensions/Networking/Runtime/NetworkServer.cs:1531)
SpawnControl.SpeedSpawn () (at Assets/Scripts/SpawnControl.cs:49)
SpawnControl.CreateSpeed () (at Assets/Scripts/SpawnControl.cs:37)
SpawnControl.Update () (at Assets/Scripts/SpawnControl.cs:28)


    // Update is called once per frame
    void Update()
    {
        if(isServer)
        {
           CreateSpeed();
        }
    }

    public void CreateSpeed()
    {
        if (SpeedBoost < 0)
        {
            SpeedBoost = 7;  
            SpeedSpawn();
        }
        else
        {
            SpeedBoost -= Time.deltaTime;
        }
    }

    public void SpeedSpawn()
    {
        int n = Random.Range(0, SpawnPoints.Count);
        GameObject go = Instantiate(SpawnItems[0], SpawnPoints[n].position, Quaternion.identity) as GameObject;
        NetworkServer.Spawn(go);
    }
2

Fixed it.
I changed Public Transfform SpawnItems;
to
Public GameObject SpawnItems;