RegisterClassEx возвращает 0

class Window {
        HINSTANCE Hinstance;
        LPCTSTR ClassName;
        ATOM ClassType;
        HWND Hwnd;
        static LRESULT CALLBACK WindProc(HWND Hwnd, UINT Msg, WPARAM WParam, LPARAM LParam) {
            return DefWindowProc(Hwnd, Msg, WParam, LParam);
        };
    public:
        Window(HINSTANCE Hinst, LPCTSTR Name, WindowStyle WStyle = WindowStyle());
        void Run();
    };
 
    Window::Window(HINSTANCE Hinst, LPCTSTR Name, WindowStyle WStyle)
        : Hinstance(Hinst), ClassName(Name), ClassType(0) {
        WNDCLASSEX WC;
        WC.cbSize = sizeof(WNDCLASSEX);
        WC.style = CS_HREDRAW | CS_VREDRAW;
        WC.lpfnWndProc = Window::WindProc;
        WC.cbClsExtra = 0;
        WC.cbWndExtra = 0;
        WC.hInstance = Hinst;
        WC.hIconSm = LoadIcon(nullptr, IDI_APPLICATION);
        WC.hCursor = LoadCursor(nullptr, IDC_ARROW);
        WC.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
        WC.lpszMenuName = nullptr;
        WC.lpszClassName = Name;
        WC.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
        ClassType = RegisterClassEx(&WC);
        Hwnd = CreateWindow(Name, 0, WStyle.GetStyle(), 0, 0, 0, 0, nullptr, nullptr, Hinstance, 0);
    }
 
    void Window::Run() {
        ShowWindow(Hwnd, SW_SHOWNORMAL);
        MSG msg;
        while(GetMessage(&msg, NULL, 0, 0)) {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
    }