Warning: connect.session() MemoryStore is not designed for a production environment, as it will leak memory, and will not scale past a single process

Using cookie-session instead of express-session solved this issue for me.

You store the session on the client and not on the server with cookies.

Simply:

1. Install it with npm install cookie-session
2. Change
   

   var session = require('express-session');

   to var session = require('cookie-session');