Lv_obj_clean(lv_scr_act()); error

i try transition between on screens, but lv_obj_clean(lv_scr_act()); this function only working one time and when i tried second return a error code. How can fix ? by the way I use littleVgl v6.
My code;

void tos_firstScreen_Update(lv_task_t * t){
	screenCounter++;
	if(screenCounter==20){
		lv_obj_clean(lv_scr_act()); //Working at here
		tos_Gui_Init();
		lv_task_del(t);
		return;
	}
}
```		if(!READ_LEFT_BTN){
			lv_obj_clean(lv_scr_act()); tos_MainScreen_Init(1,1); //But i get error here
		}

type or paste code here

I haven’t tested, but maybe lv_task_del() breaks it.

Is it working without it?