I am using jquery ajax datatable. I dont know why this error appears to my browser. I think my code doesn't have an error. Can someone know what is the mistake in this?

Error that i get DataTables warning: table id=users-table - Ajax error. For more information about this error, please see http://datatables.net/tn/7

  public function datatables()
    {

        $booking = Booking::with('users','rooms')
        ->select(['id','user_id','room_id','start_datetime','end_datetime','points','price'])- 
         >OrderBy('created_at','DESC');

        return Datatables::of($booking)

        ->addColumn('startEndDateColumn', function($row){
            $time = new DateTime($row->start_datetime);
            $start_date = $time->format('j-n-Y');

            $time = new DateTime($row->end_datetime);
            $end_date = $time->format('j-n-Y');

            return $start_date . ' - ' . $end_date;
        })
        ->addColumn('startEndTimeColumn', function($row){
            $time = new DateTime($row->start_datetime);
            $start_time = $time->format('h:i a');

            $time = new DateTime($row->end_datetime);
            $end_time = $time->format('h:i a');

            return $start_time . ' - ' . $end_time;
        })
        ->make(true);
    }