ClosedXML OutOfMemoryException

gistfile1.cs

private static byte[] ConvertReportToExcel(List<Dictionary<string, object>> report)
{
    var file = new XLWorkbook();
    var sheet = file.Worksheets.Add("Report");
    if (report.Count() == 0) {
        sheet.Cell("A1").SetValue("Report is empty");
    } else {
        // First row filled with keys
        var firstRow = report.ElementAt(0);
        for (int j = 0; j < firstRow.Count; j++) {
            var cell = sheet.Row(1).Cell(j + 1);
            cell.SetValue(firstRow.Keys.ElementAt(j));
            sheet.Row(1).Style.Fill.BackgroundColor = XLColor.LightGray;
            sheet.Row(1).Style.Font.Bold = true;
            sheet.Row(1).Style.Alignment.Horizontal = XLAlignmentHorizontalValues.Center;
        }
        // Values
        for (int i = 0; i < report.Count(); i++) {
            var row = report.ElementAt(i);
            for (int j = 0; j < row.Count; j++) {
                var cell = sheet.Row(i + 2).Cell(j + 1);
                var cellVal = row.Values.ElementAt(j);
                cell.SetValue(cellVal);
            }
        }
        sheet.SheetView.FreezeRows(1);
        sheet.Range(sheet.Row(1).Cell(1).Address, sheet.LastCellUsed().Address).CreateTable();
    }
    using (var stream = new MemoryStream()) {
        file.SaveAs(stream);
        return stream.ToArray();
    }
}