Unity Netcode Networked GameObject not Appearing on Client - unity3d

Question

I am trying to build a multiplayer tile-based strategy game. From my understanding, I should create a "Player" GameObject, and then the map should be stored as a collection of GameObjects with a NetworkObject component to sync from client to server.
However, I am having issues syncing GameObjects between the host and the client. When a server is created, only the server should generate the map (map generation code marked). When a player connects, they should get their own game component.
namespace HelloWorld
{
public class HelloWorldManager : MonoBehaviour
{
public GameObject networkedPrefab;
void OnGUI()
{
GUILayout.BeginArea(new Rect(10, 10, 300, 300));
if (!NetworkManager.Singleton.IsClient && !NetworkManager.Singleton.IsServer)
{
if (GUILayout.Button("Client")) NetworkManager.Singleton.StartClient();
if (GUILayout.Button("Server")) {
// Generate 'map' here of 10 items
for (int i = 0; i < 10; i++) {
var go = Instantiate(networkedPrefab);
go.transform.position = new Vector2((i - 5), 0);
go.gameObject.name = "Circle-" + i;
}
NetworkManager.Singleton.StartServer();
}
}
else
{
StatusLabels();
SubmitNewPosition(); // Adds button for player to randomly move their position
}
GUILayout.EndArea();
}
static void SubmitNewPosition()
{
if (GUILayout.Button(NetworkManager.Singleton.IsServer ? "Move" : "Request Position Change"))
{
if (NetworkManager.Singleton.IsServer && !NetworkManager.Singleton.IsClient )
{
foreach (ulong uid in NetworkManager.Singleton.ConnectedClientsIds)
NetworkManager.Singleton.SpawnManager.GetPlayerNetworkObject(uid).GetComponent<HelloWorldPlayer>().Move();
}
else
{
var playerObject = NetworkManager.Singleton.SpawnManager.GetLocalPlayerObject();
var player = playerObject.GetComponent<HelloWorldPlayer>();
player.Move();
}
}
}
}
}
Here is what I am getting with 0 clients (The map is represented by circles):
After adding a client, here is what I get on the server side:
... And on the client side I get nothing:
Here are the prefabs I used:
Any help to get things to sync across the server and client would be greatly appreciated.

Answer 1

As your objects are generated at runtime (rather than saved in the scene), you need to call Spawn() on the network object. Adding a NetworkObject is enough if your objects are saved in the scene but dynamically instantiating them at runtime requires a spawn call.
For your map:
for (int i = 0; i < 10; i++) {
var go = Instantiate(networkedPrefab);
go.transform.position = new Vector2((i - 5), 0);
go.gameObject.name = "Circle-" + i;
go.GetComponent<NetworkObject>().Spawn();
}
As an aside, I think you need to start the server before doing the spawn.