Trying to fix the build error.

Author: ilonatommy

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.EventDispatch.cs

@@ -74,7 +74,7 @@ private Task ReturnErrorResponse(string detailedMessage)
             : Task.CompletedTask;
     }
 
-    public void SetNotFoundResponse()
+    private void SetNotFoundResponse(object sender, EventArgs args)
     {
         _httpContext.Response.StatusCode = StatusCodes.Status404NotFound;
     }

src/Components/Endpoints/src/Rendering/EndpointHtmlRenderer.cs

@@ -79,10 +79,10 @@ internal async Task InitializeStandardComponentServicesAsync(
         var navigationManager = httpContext.RequestServices.GetRequiredService<NavigationManager>();
         ((IHostEnvironmentNavigationManager)navigationManager)?.Initialize(GetContextBaseUri(httpContext.Request), GetFullUri(httpContext.Request));
 
-        navigationManager?.NotFoundEvent += (sender, args) =>
+        if (navigationManager != null)
         {
-            SetNotFoundResponse();
-        };
+            navigationManager.NotFoundEvent += SetNotFoundResponse;
+        }
 
         var authenticationStateProvider = httpContext.RequestServices.GetService<AuthenticationStateProvider>();
         if (authenticationStateProvider is IHostEnvironmentAuthenticationStateProvider hostEnvironmentAuthenticationStateProvider)