Starting a client on standalone.exe not working but i works on editor play

Questions & Answers
1

This code snippet here causes the error below the code only on standalone exe. What could be the proleme? Thanks for help.

using UnityEngine;
using System.Collections;
using UnityEngine.Networking;
using UnityEngine.UI;

public class MyNetworkManager : NetworkManager
{
    public bool isAtStartup = true;
    void Update()
    {
        if (isAtStartup)
        {
            if (Input.GetKeyDown(KeyCode.X))
            {
                SetPort();
                StartServer();
                StartClient();
   //             StartHost();            // same error for startclient() or starthost()
                isAtStartup = false;
            }
        }
    }
}

NullReferenceException: Object reference not set to an instance of an object
at UnityEngine.Networking.NetworkTransform.SerializeMode3D (UnityEngine.Networking.NetworkWriter writer) [0x0005c] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkTransform.cs:251

at UnityEngine.Networking.NetworkTransform.OnSerialize (UnityEngine.Networking.NetworkWriter writer, Boolean initialState) [0x0005a] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkTransform.cs:195

at UnityEngine.Networking.NetworkIdentity.UNetSerializeAllVars (UnityEngine.Networking.NetworkWriter writer) [0x00010] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkIdentity.cs:421

at UnityEngine.Networking.NetworkServer.SendSpawnMessage (UnityEngine.Networking.NetworkIdentity uv, UnityEngine.Networking.NetworkConnection conn) [0x000d0] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkServer.cs:1403

at UnityEngine.Networking.NetworkServer.ShowForConnection (UnityEngine.Networking.NetworkIdentity uv, UnityEngine.Networking.NetworkConnection conn) [0x0000b] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkServer.cs:1202

at UnityEngine.Networking.NetworkConnection.AddToVisList (UnityEngine.Networking.NetworkIdentity uv) [0x0000d] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkConnection.cs:497

at UnityEngine.Networking.NetworkIdentity.AddObserver (UnityEngine.Networking.NetworkConnection conn) [0x000b9] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkIdentity.cs:715

at UnityEngine.Networking.NetworkServer.SetClientReadyInternal (UnityEngine.Networking.NetworkConnection conn) [0x001cb] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkServer.cs:1191

at UnityEngine.Networking.NetworkServer.SetClientReady (UnityEngine.Networking.NetworkConnection conn) [0x00000] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkServer.cs:1125

at UnityEngine.Networking.NetworkManager.OnServerReady (UnityEngine.Networking.NetworkConnection conn) [0x00024] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkManager.cs:772

at UnityEngine.Networking.NetworkManager.OnServerReadyMessageInternal (UnityEngine.Networking.NetworkMessage netMsg) [0x00014] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkManager.cs:653

at UnityEngine.Networking.NetworkConnection.HandleReader (UnityEngine.Networking.NetworkReader reader, Int32 receivedSize, Int32 channelId) [0x0011f] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkConnection.cs:416

at UnityEngine.Networking.NetworkConnection.HandleBytes (System.Byte buffer, Int32 receivedSize, Int32 channelId) [0x00007] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkConnection.cs:372

at UnityEngine.Networking.NetworkConnection.TransportRecieve (System.Byte bytes, Int32 numBytes, Int32 channelId) [0x00000] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkConnection.cs:522

at UnityEngine.Networking.NetworkServer.InternalUpdate () [0x0020b] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkServer.cs:702

at UnityEngine.Networking.NetworkServer.Update () [0x0000c] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkServer.cs:564

at UnityEngine.Networking.NetworkIdentity.UNetStaticUpdate () [0x00000] in C:\buildslave\unity\build\Extensions\Networking\Runtime\NetworkIdentity.cs:909

(Filename: C:/buildslave/unity/build/Extensions/Networking/Runtime/NetworkTransform.cs Line: 251)

3

You can’t be client and server at the same time. This is a special case and is called “Host”.

  • Use StartServer if this PC should be a dedicated server
  • Use StartHost if this PC should be a server as well as a client.
  • Use StartClient if this PC should by a client.

Never use two of those methods in the same application.

2

I fixed the same error - I had a UNET build which worked as server in the editor but did not work when built as standalone.

The problem for me was that I had an object that disabled itself in OnStart() which contained objects that had NetworkIdentities.

I don’t 100% understand why, but when building standalone those objects are cached by the server before Start() is called and then they are attempted to be transmitted to clients, but the server produces this error because he objects are no longer active.

It can help to use the line

LogFilter.currentLogLevel = (int)LogFilter.FilterLevel.Debug;

in a Start() somewhere (eg your NetworkManager) to get more debug info out of UNET. This is what led me to find out what was going on.