No message system available error after SDL_ShowSimpleMessageBox

I’m trying to launch a simple message box in my program
System is Arch Linux with sdl2 version == 2.0.12-2
Using GNOME with X11 backend
And my code is:

static void showLinuxMessageError(const std::string message)
{
if(SDL_ShowSimpleMessageBox(SDL_MESSAGEBOX_ERROR, "Service Error", message.c_str(), NULL))
	std::cerr << "SDL_ShowSimpleMessageBox error: " << SDL_GetError() << std::endl;
}

The code runs after SDL_Init() and before SDL_Quit()
The error I get shows:

SDL_ShowMessageBox error: No message system available

I have created a SDL_Window object in another class, but I don’t want to pass it here (supposed to be static function).
Any solutions?

I found a possible alternative on Linux.
libnotify
Seems that it is limited to GNOME, but it works well and easy to implement.