Answer by Liyun Zhang - MSFT for .Net Maui App bar graph throwing XLS0414 error unexpectedly

The error occurs at line 24 of the .xaml i.e. "<sfChart:BarSeries ItemsSource="{Binding SalesDataCollection}"" on the 'sfChart:BarSeries' part.

This is because there is no BarSeries class in the Syncfusion.Maui.Charts. If you want to use BarChart, you can check the official sample about the BarChart.

<chart:SfCartesianChart IsTransposed="True"><chart:SfCartesianChart.XAxes><chart:CategoryAxis/></chart:SfCartesianChart.XAxes><chart:SfCartesianChart.YAxes><chart:NumericalAxis/></chart:SfCartesianChart.YAxes>   <chart:ColumnSeries ItemsSource="{Binding Data}"                        XBindingPath="XValue"                        YBindingPath="YValue"/></chart:SfCartesianChart>

In addition, you can check all the Chart Types in the official doc.