[Solved]-Highchart tick interval-Highcharts

first of all, remove the 'categories' property on xaxis, this has no meaning on a datetime axis. note that datetime axes are based on milliseconds, so an interval of one hour is expressed as 3600 * 1000. see api highcharts, tickinterval

use this config for the xaxis.

xaxis: {
        type: "datetime",    
        datetimelabelformats: {
            day: '%h'
        },
        tickinterval: 3600 * 1000
}, 

see here for a working demo on js bin.