Empty Pdf file generated with FPDF library in WordPress plugin

I am currently implementing a pdf export functionality within a wordpress plugin i'm developing but the pdf file generated when i click on export button is empty. To implement the export i use FPDF library

Ive put the code which uses FPDF in a function which is executed by the wp_ajax_ action hook. Here is the code:

?php

require_once plugin_dir_path( __FILE__ ) . 'fpdf/fpdf.php';

function pdf_pull_wpse_212972() {

  $pdf = new FPDF('p','mm','a4');
  $pdf-SetFont('arial','b',14);
  $pdf-AddPage();
  $pdf-Cell(40,10,'Referrer URL',1,0,'C');
  $pdf-Cell(40,10,'User IP Address',1,0,'C');
  $pdf-Cell(40,10,'User Agent',1,0,'C');
  $pdf-Cell(40,10,'Browser',1,0,'C');
  $pdf-Cell(40,10,'OS',1,0,'C');
  $pdf-Output();

  wp_die();

}

add_action('wp_ajax_pdf_pull','pdf_pull_wpse_212972'); 

Here is the jQuery code executed when i click on the export button

jQuery(document).ready(function($) {

  
  jQuery('#pdf-export-btn').click(function(){

    var data = {
      'action': 'pdf_pull',
    };
    
    jQuery.post(tclisecure.ajax_url, data, function(response) {


        var downloadLink = document.createElement(a);
        var fileData = [response];

        var blobObject = new Blob(fileData,{
            type: application/pdf
          });

        var url = URL.createObjectURL(blobObject);
        downloadLink.href = url;
        downloadLink.download = tracked_info.pdf;

        /*
        * Actually download PDF
        */
        document.body.appendChild(downloadLink);
        downloadLink.click();
        document.body.removeChild(downloadLink);
      
    });

  });


});