1 Line Fix for your Unity Project

https://game.courses/mp/ - Multiplayer Mastery Course

* for anyone who wants the code, here it is
using Unity.Services.Core;
using UnityEngine;
using UnityEngine.SceneManagement;

public class Bootstrapper : MonoBehaviour
{
async void Start()
{
Application.runInBackground = true;
await UnityServices.InitializeAsync();

if (SceneManager.loadedSceneCount == 1)
SceneManager.LoadScene("CarSelection", LoadSceneMode.Additive);
}

[RuntimeInitializeOnLoadMethod(RuntimeInitializeLoadType.BeforeSceneLoad)]
static void Init()
{
#if UNITY_EDITOR
var currentlyLoadedEditorScene = SceneManager.GetActiveScene();
#endif

if (SceneManager.GetSceneByName("Bootstrapper").isLoaded != true)
SceneManager.LoadScene("Bootstrapper");

#if UNITY_EDITOR
if (currentlyLoadedEditorScene.IsValid())
SceneManager.LoadSceneAsync(currentlyLoadedEditorScene.name, LoadSceneMode.Additive);
#else
SceneManager.LoadSceneAsync("CarSelection", LoadSceneMode.Additive);
#endif
}
}