How to Center Bar in Flot Char js

i have, some problem with flot.js, in my chart xaxis is not center with the bar, i try with align: 'center' but it's not work, what I want is the xaxis (date label) exactly below the chart this is my code

 $.plot('#grafik-presensi', [data], {
        series: {
                bars: {
                    show: true,
                    barWidth: 0.6,
                    align:'center',
                    fill: true,
                    fillColor: {
                        colors: [{
                            opacity: 0.9
                        }, {
                            opacity: 0.9
                        }]
                    }
                }
            },
            colors: ['#25476a'],
            yaxis: {
                },
            xaxis: {
                    ticks: ticks,
                    
            },
            grid: {
                hoverable: true,
                clickable: true,
                tickColor: '#eeeeee',
                borderWidth: 0
            },
            legend: {
                show: true,
                position: 'nw'
            },
            tooltip: {
                show: true,
                content: 'Presensi %x, Jumlah %y'
            }

    });
});