Just installed Umbraco Forms on this site with Autofac running IOC. All other content and setting trees still work, and I can create forms, but I don't see the forms tree under the forms section of the site...

All my API endpoints are still working

{  
   "Message":"An error has occurred.",
   "ExceptionMessage":"Object reference not set to an instance of an object.",
   "ExceptionType":"System.NullReferenceException",
   "StackTrace":"   at Umbraco.Web.Trees.ApplicationTreeExtensions.<TryGetRootNodeFromControllerTree>d__4.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at Umbraco.Web.Trees.ApplicationTreeController.<GetRootForMultipleAppTree>d__12.MoveNext()\r\n--- End of stack trace from previous location where exception was thrown ---\r\n   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)\r\n   at System.Runtime.CompilerServices.TaskAwaiter`1.GetResult()\r\n   at Umbraco.Web.Trees.ApplicationTreeController.<GetApplicationTrees>d__4.MoveNext()"
}

Here is my container code:

protected override void OnApplicationStarted(object sender, EventArgs e)
        {
            base.OnApplicationStarted(sender, e);
            var builder = new ContainerBuilder();
            // Register your MVC controllers.
            builder.RegisterControllers(typeof(Controllers.HomepageController).Assembly);
            builder.RegisterApiControllers(typeof(Umbraco.Web.UmbracoApplication).Assembly);
            builder.RegisterApiControllers(typeof(Controllers.HomepageController).Assembly);
            
            builder.RegisterModule<AutofacWebTypesModule>();
            builder.RegisterModule<Modules.DalModule>();
            builder.RegisterModule<Modules.BllModule>();
            // OPTIONAL: Register model binders that require DI.
            builder.RegisterModelBinders(System.Reflection.Assembly.GetExecutingAssembly());
            builder.RegisterModelBinderProvider();
            // OPTIONAL: Register web abstractions like HttpContextBase.
            builder.RegisterModule<AutofacWebTypesModule>();
            // OPTIONAL: Enable property injection in view pages.
            builder.RegisterSource(new ViewRegistrationSource());
            // OPTIONAL: Enable property injection into action filters.
            builder.RegisterFilterProvider();
            // Set the dependency resolver to be Autofac.
            var container = builder.Build();
            var resolver = new Autofac.Integration.WebApi.AutofacWebApiDependencyResolver(container);
            GlobalConfiguration.Configuration.DependencyResolver = resolver;
            DependencyResolver.SetResolver(new AutofacDependencyResolver(container));
            Logic.NuPickerDataSource.DataSourceFactory = type => DependencyResolver.Current.GetService(type);
        }