ExcelDataReader: ExcelDataReader - Error: Invalid file signature

So I’m trying to read my excel file that is consist of 8 header titles No. Mchn. EnNo. Name. Mode. IOMd. Date_Time

and a 300+ of data. and the data grid view is not reading all of my data and the error keeps appearing,… what should I do?

` private void comboBox1_SelectedIndexChanged(object sender, EventArgs e) { DataTable dt = tableCollection[cboSheet.SelectedItem.ToString()]; dataGridView1.DataSource = dt;

    }

    DataTableCollection tableCollection;
    private void btnBrowse_Click(object sender, EventArgs e)
    {
        using (OpenFileDialog openFileDialog = new OpenFileDialog() { Filter = "MS Excel 2007 onwards |*xls" })
        // "Excel 97-2003 Workbook | *.xls | Excel Workbook | *.xlsx" })
        {

            if (openFileDialog.ShowDialog() == DialogResult.OK)
            {
                txtFilename.Text = openFileDialog.FileName;
                using (var stream = File.Open(openFileDialog.FileName, FileMode.Open, FileAccess.Read))
                {
                    using (IExcelDataReader reader= ExcelReaderFactory.CreateReader(stream))           
                    {
                        DataSet result = reader.AsDataSet(new ExcelDataSetConfiguration()
                       
                        {
                            ConfigureDataTable = (_) => new ExcelDataTableConfiguration() { UseHeaderRow = true }
                        });
                        tableCollection = result.Tables;
                        cboSheet.Items.Clear();
                        foreach (DataTable table in tableCollection)
                        cboSheet.Items.Add(table.TableName); //add sheet to combobox
                    }
                }
            }
        }`