Data is not displayed although info shows correct numbre of records and empty rows odd/even

hoekbrwr

The following code does produce rows, but all rows are empty.

function Deelnemers(){
        var table = jQuery('#deelnemers');
        var public_spreadsheet_url = 'https://docs.google.com/spreadsheets/d/1HkBjID68nmFGL4nL1TXGWmD_5CtexIEeebgc0jDQzYk/pubhtml';
        Tabletop.init({ key: public_spreadsheet_url,
                             callback: showInfo,
                             simpleSheet: true,
                             debug: false });
        function showInfo(data) {
            table.DataTable({
                data: data,
                stateSave: true,
                processing: true,
                dom: '<if>rt<lp>',
                paging: false,
                columns: [
                    {title: 'SN', 'sTitle': 'Start#', 'sClass': 'center', sWidth: '5%'},
                    {title: 'Naam Heer', 'sTitle': 'Naam Heer', 'sClass': 'left', sWidth: '35%'},
                    {title: 'Naam Dame', 'sTitle': 'Naam Dame', 'sClass': 'left', sWidth: '35%'},
                    {title: 'Klassen', 'sTitle': 'Klasse(n)', 'sClass': 'left', sWidth: '15%'},
                    {title: 'Leraar', 'sTitle': 'Leraar(Afk.)', 'sClass': 'left', sWidth: '10%'},
                ],
                order: [[0, "asc"]],
                language: {
                    "decimal":        "",
                    "emptyTable":     "Geen gegevens beschikbaar in de tabel",
                    "info":           "_START_ tot _END_ van  _TOTAL_ items",
                    "infoEmpty":      "0 tot 0 van 0 rijen",
                    "infoFiltered":   "(gefilterd uit _MAX_ totaal aantal items)",
                    "infoPostFix":    "",
                    "thousands":      ".",
                    "lengthMenu":     "Aantal _MENU_ items",
                    "loadingRecords": "Laden...",
                    "processing":     "Verwerken...",
                    "search":         "Zoeken:",
                    "zeroRecords":    "Geen passende items gevonden",
                    "paginate": {
                        "first":      "Eerste",
                        "last":       "Laatste",
                        "next":       "Volgende",
                        "previous":   "Vorige"
                    },
                    "aria": {
                        "sortAscending":  ": activeren voor oplopende sortering",
                        "sortDescending": ": activeren voor aflopende sortering"
                    }                   
                }
            });
        }
}

I have been looking to the console and I can see all records are receivedfrom Tabletop in the variable data as an array of Objects! What I see is a perfect table with header and the correct number of rows odd/even, but the data has not been added to the table data cells.
I am quite new to this, so I might have missed some instruction how to get them visible. Do I need to add a certain class to the

<

table>? What am I missing???