Why can't I get the data of 2019-07-01~2019-07-31 by using dailyTrends Api

[fortune-cook1e]

  googleTrends.dailyTrends({
    trendDate: new Date('2019-07-01'),
    geo: 'US',
  }, function(err, results) {
    if (err) {
      console.log(err);
    }else{
      console.log(results);
    }
  });

The result

{"default":{"trendingSearchesDays":[]}}