Q:

Fourth y axis does not show labels in Highcharts

I have a chart with 4 series plotted, I decided to put two y axis on each side of the graph, which worked. The only trouble I am having is showing all the labels of each y axis, specifically the last one in the series that I have named "Stuff Data", it is apparently using the Voltage data's y axis
Please see:
https://jsfiddle.net/Lprm4ofw/51/
I have tried switching the order of the series and yAxis but always the last one's label would not show up. I also tried playing with the margins in case it's hidden but it is definitely not. What can I try to do to fix it? here is the code:
Highcharts.chart('container', {
    chart: {
        zoomType: 'xy',
        type: 'spline'
    },
    title: {
        text: 'Whatever'
    },
    xAxis: [{
        categories: ['Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
            'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'],
        crosshair: true
    }],
      yAxis: [{ // Primary yAxis
            title: {
                text: 'Voltage',
                style: {
                    color: Highcharts.getOptions().colors[2]
                }
            },
                        labels: {
                format: '{value} V',
                style: {
                    color: Highcharts.getOptions().colors[2]
                }
            },
            opposite: true

        }, { // Secondary yAxis
            title: {
                text: 'Current',
                style: {
                    color: Highcharts.getOptions().colors[0]
                }
            },
            labels: {
                format: '{value} C',
                style: {
                    color: Highcharts.getOptions().colors[0]
                }
            },
        },
        { // Third yAxis
              gridLineWidth: 0,
              title: {
                  text: 'Temperature',
                  style: {
                      color: Highcharts.getOptions().colors[3]
                  }
              },
              labels: {
                  format: '{value}°C',
                  style: {
                      color: Highcharts.getOptions().colors[3]
                  }
              },
          opposite: true

          },
          { // Fourth yAxis
                title: {
                    text: 'stuff',
                    style: {
                        color: Highcharts.getOptions().colors[4]
                    }
                },
                labels: {
                    format: 'WHEREAMI',
                    style: {
                        color: Highcharts.getOptions().colors[4]
                    }
                },

      }],
    tooltip: {
        shared: true
    },
    legend: {
        layout: 'vertical',
        align: 'left',
        x: 80,
        verticalAlign: 'top',
        y: 55,
        floating: true,
        backgroundColor: (Highcharts.theme && Highcharts.theme.legendBackgroundColor) || '#FFFFFF'
    },
    series: [
     {
        name: 'Voltage Data',
        data: [10.0, 20.79, 13.5, 18.8],
        yaxis: 0,
    },
    {
        name: 'Current Data',
        yAxis: 1,
        data: [1, 2, 3 , 4],

    }, {
        name: 'Temperature Data',
        yAxis: 2,
        data: [4, 5, 6 , 9]

    }, {
        name: 'Stuff Data',
        data: [7.0, 6.9, 9.5],
        yaxis: 3,
    }]
});

A:

You have to use correct property name, xaxis is not the same as xAxis:
series: [
  {
    name: 'Voltage Data',
    data: [10.0, 20.79, 13.5, 18.8],
    yAxis: 0,
  },
  {
    name: 'Current Data',
    yAxis: 1,
    data: [1, 2, 3, 4],

  }, {
    name: 'Temperature Data',
    yAxis: 2,
    data: [4, 5, 6, 9]

  }, {
    name: 'Stuff Data',
    data: [7.0, 6.9, 9.5],
    yAxis: 3,
  }
]

Live demo: https://jsfiddle.net/BlackLabel/6wrahgko/

