title: how to debug cookie rejection by the browser
body: <p>Using either Chrome (Version 59.0.3071.115 (Official Build) (64-bit)) or Firefox (developer edition 56.0b3 (64-bit)), I am unable to understand why I do not see the cookie sent in the response header, get stored in the browser local storage.</p>
  
  <p>My HTTP request header is as follows:</p>
  
  <pre><code>Host: localhost:3000
  User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:56.0) Gecko/20100101 Firefox/56.0
  Accept: application/json
  Accept-Language: en-US,en;q=0.5
  Accept-Encoding: gzip, deflate
  Referer: http://localhost:3000/SignIn
  content-type: application/json
  origin: http://localhost:3000
  Content-Length: 46
  Connection: keep-alive
  </code></pre>
  
  <p>My response header is as follows:</p>
  
  <pre><code>x-powered-by: Express
  content-type: application/json; charset=utf-8
  access-control-allow-origin: *
  Vary: *
  content-length: 32
  etag: W/"20-LcTp1bBlcTS0d04Fav3DxiGJgW0"
  set-cookie: connect.sid=s%3ABBRbPNpMXcweAtfATcULtOOzgMwlBrtC.qX8a9M%2BrsKsjhdeRL7eAyzFrkjQMOoWw36DIhSdhiGQ; Domain=http://localhost:3000; Path=/; HttpOnly
  date: Sat, 19 Aug 2017 08:15:01 GMT
  connection: close
  </code></pre>
  
  <hr>
  
  <p>I do not see any cookie being stored, using the 'Storage' tab of Firefox dev tools or the 'Application' tab of Chrome. Neither can I find any error message in these tools that tell me why the cookie was not stored.</p>
  
  <p>What am I missing?</p>