Why does my Flask website fail to export data to an Excel file, despite no errors?

I have developed a simple python Flask website where my goal is users can fill a form and then be able to view their previous inputs in a html table and be able to choose and export some rows of the table in a excel file. Although the site is working fine in all other aspects (data are correctly being stored in the database, they also display fine in a table format etc), the export to an excel file can't seem to work...

The part of my html code for the page that tries to export the html table to an excel is the following :

      <button id="exportButton" class="btn btn-primary">Export to Excel</button>
    <script>
      $(document).ready(function () {
        $('#projectTable').DataTable();

        $('#exportButton').click(function () {
          var selectedRows = [];
          $('.row-checkbox:checked').each(function () {
            var rowData = $(this).closest('tr').find('td').map(function () {
              return $(this).text();
            }).get();
            selectedRows.push(rowData);
          });

          // Send selectedRows to the server for export
          $.ajax({
            type: 'POST',
            url: '/export',
            data: JSON.stringify(selectedRows),
            contentType: 'application/json',
            success: function (response) {
              // Handle the server's response, if needed
              // For example, you can show a success message or trigger a file download
              console.log('Export successful!');
            },
            error: function (xhr, status, error) {
              // Handle errors, if any
              console.error('Export error:', error);
            }
          });
        });
      });
    </script>
  </body>
</html>

while my /export endpoint which is used in the ajax request is :

@views.route('/export', methods=['POST'])
@login_required
def export():
    selected_rows = request.get_json()  # Get the selected rows' data from the request

    # Create a DataFrame from the selected rows' data
    df = pd.DataFrame(selected_rows, columns=['header1', 'header2', 'header3', 'header4',
                                              'header5', 'header6',
                                              'header7',
                                              'header8'])

    # Generate an Excel file from the DataFrame
    excel_file = io.BytesIO()
    df.to_excel(excel_file, index=False)
    excel_file.seek(0)  # Move the file pointer to the beginning of the file
    # Prepare the response headers
    headers = {
        'Content-Disposition': 'attachment; filename=selected_rows.xlsx',
        'Content-Type': 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet'
    }

    # Return the Excel file contents as the response
    return Response(excel_file, headers=headers)

Although i get a 200 response back from the server ('127.0.0.1 - - [24/May/2023 19:21:00] "POST /export HTTP/1.1" 200 -'), no excel file is being downloaded (exported) to the client. Why is that?

I eventually got rid of the /export endpoint and fixed the issue with solely javascript code. For anyone interested, this is the code i used :

    <script src="https://unpkg.com/xlsx/dist/xlsx.full.min.js"></script>
    <script type="text/javascript">
      function getSelectedRows() {
        const checkboxes = document.querySelectorAll(".row-checkbox");
        const selectedRows = [];
    
        checkboxes.forEach(function (checkbox) {
          if (checkbox.checked) {
            const row = checkbox.closest("tr");
            selectedRows.push(row);
          }
        });
    
        return selectedRows;
      }
    
      function exportReportToExcel() {
        const selectedRows = getSelectedRows();
    
        if (selectedRows.length === 0) {
          alert("No rows selected. Please select at least one row.");
          return;
        }
    
        const table = document.createElement("table");
        const tableBody = document.createElement("tbody");
    
        selectedRows.forEach(function (row) {
          tableBody.appendChild(row.cloneNode(true));
        });
    
        table.appendChild(tableBody);
    
        const wb = XLSX.utils.table_to_book(table, { sheet: "Sheet 1" });
        XLSX.writeFile(wb, "file.xlsx");
      }
    </script>