[Command]-Function By Client is not called on Server

Questions & Answers
1

My PlayerObject has the following script:

[Command]
void CmdFire()
{
    // Create the Bullet from the Bullet Prefab
    var bullet = (GameObject)Instantiate(
        bulletPrefab, cameraRig.position, cameraRig.rotation);

    // Spawn the bullet on the Clients
    NetworkServer.Spawn(bullet);

    // Destroy the bullet after 2 seconds
    Destroy(bullet, 2.0f);
}

The bullet prefab has a networkid, networktransform and its script is from networkingbehaviour. Prefab is registered in the NetworkManager. Everything works fine if the host-client runs the CmdFire() function. The bullet will spawn for all Clients.

But if I execute the CmdFire() function on a client, the code is never executed on the server, even though it should. No object is created on the server, not even for the host-client.

I am using Unity 2017.3.

2

I think i found the error source:

cameraRig.position, cameraRig.rotation

as these are not SyncVars, Instantiate is not executed. Hence, Nullpointer exception occurs.