No gridlines visible in an image

[jszuminski]

Actual behaviour

Use the following JSON file to generate a PNG:

{
  "chart": {
    "type": "column",
    "backgroundColor": "transparent",
    "style": {
      "fontFamily": "sans-serif"
    },
    "polar": true
  },
  "title": "",
  "credits": false,
  "legend": {
    "enabled": false
  },
  "plotOptions": {
    "series": {
      "grouping": false,
      "pointPadding": 0,
      "groupPadding": 0,
      "stacking": "normal"
    }
  },
  "xAxis": {
    "labels": {
      "useHTML": true,
      "enabled": true,
      "style": {
        "fontSize": "14px",
        "color": "#444444"
      }
    },
    "categories": [
      "Abundance & Generosity<br/>70%",
      "Connection & Compassion",
      "Courage & Vulnerability",
      "Candor & Debate",
      "Action & Accountability"
    ],
    "gridZIndex": 10,
    "gridLineColor": "gray"
  },
  "yAxis": {
    "reversedStacks": false,
    "tickInterval": 20,
    "gridZIndex": 10,
    "gridLineColor": "gray",
    "min": 0,
    "max": 100,
    "showLastLabel": true,
    "showFirstLabel": false,
    "labels": {
      "style": {
        "color": "#444444"
      },
      "distance": 20,
      "y": 13
    }
  },
  "series": [
    {
      "name": "Abundance & Generosity",
      "color": "#41a3d1",
      "data": [
        [
          0,
          70
        ]
      ]
    },
    {
      "name": "Connection & Compassion",
      "color": "#c93452",
      "data": [
        [
          1,
          73
        ]
      ]
    },
    {
      "name": "Courage & Vulnerability",
      "color": "#8a136a",
      "data": [
        [
          2,
          58
        ]
      ]
    },
    {
      "name": "Candor & Debate",
      "color": "#fcc200",
      "data": [
        [
          3,
          63
        ]
      ]
    },
    {
      "name": "Action & Accountability",
      "color": "#5bbaaf",
      "data": [
        [
          4,
          48
        ]
      ]
    }
  ]
}

If you use this config in JSFiddle there will be no problems: https://jsfiddle.net/wittski/hjxodgz9/1/ but if you do on the server https://export.highcharts.com/ the gridlines will not be displayed

[wittsparks]

I found a workaround for this. If you set the x axis label font size to 10px and the chart width to 500, the grid lines will appear, at least on my local export server. It seems related to this

[jszuminski]

Internal note: works via SVG exporting through the exporting.js module: https://jsfiddle.net/65cvbrxo/