title: Magento 2.3 Web Setup Wizard Blank
body: <p>I got a blank page (to be exact, there is a navigator background bar) when go to System -> Web Setup Wizard in Magento 2.3.2 Admin Panel.</p>
  
  <p>I checked via the development tool of chrome, and found those 403 response</p>
  
  <pre><code>GET http://mysite/setup/index.php/navigation 403 (Forbidden)
  Possibly unhandled rejection: {"data":"Access denied.\n","status":403,"config":{"method":"GET","transformRequest":[null],"transformResponse":[null],"jsonpCallbackParam":"callback","url":"index.php/navigation","headers":{"Accept":"application/json, text/plain, */*","Cache-Control":"no-cache, no-store, must-revalidate","Pragma":"no-cache","Expires":0}},"statusText":"Forbidden","xhrStatus":"complete"}
  
  GET http://mysite/setup/index.php/navigation/side-menu 403 (Forbidden)
  GET http://mysite/setup/index.php/navigation/header-bar 403 (Forbidden)
  POST http://mysite/setup/index.php/session/prolong 403 (Forbidden)
  </code></pre>
  
  <p>It looks like there's something to do with the permission. I checked all my directories under /setup but should be all ok</p>
  
  <p>My nginx configuration is as below,</p>
  
  <pre><code>root $MAGE_ROOT/pub;
  
  index index.php;
  autoindex off;
  charset UTF-8;
  error_page 404 403 = /errors/404.php;
  #add_header "X-UA-Compatible" "IE=Edge";
  
  # PHP entry point for setup application
  location ~* ^/setup($|/) {
      root $MAGE_ROOT;
      location ~ ^/setup/index.php {
          fastcgi_pass  unix:/tmp/php-cgi.sock;
  
          fastcgi_param  PHP_FLAG  "session.auto_start=off \n suhosin.session.cryptua=off";
          fastcgi_param  PHP_VALUE "memory_limit=756M \n max_execution_time=600";
          fastcgi_read_timeout 600s;
          fastcgi_connect_timeout 600s;
  
          fastcgi_index  index.php;
          fastcgi_param  SCRIPT_FILENAME  $document_root$fastcgi_script_name;
          include        fastcgi_params;
      }
  
      location ~ ^/setup/(?!pub/). {
          #deny all;
      }
  
      location ~ ^/setup/pub/ {
          add_header X-Frame-Options "SAMEORIGIN";
      }
  }
  </code></pre>
  
  <p>I searched on the web but found no answer. Any hint will be appreciated, thanks!</p>