https://api.highcharts.com/highstock/series.abands.zones.fillColor
series.abands.zones.fillColor | Highcharts Stock JS API Reference
Defines the fill color for the series (in area type series)
js apiserieszonesfillcolorhighcharts
https://feedback.telerik.com/maui/1596756-chart-exception-when-setting-only-the-chart-palette-fillcolor
Chart: Exception when setting only the Chart Palette FillColor
setting onlythe palettechartexceptionfillcolor