I had a similar issue. Could be due to the express-session middleware needed for passport. Fixed it by using middlewares in the following order: (Express 4)
var session = require('express-session');
// required for passport session
app.use(session({
secret: 'secrettexthere',
saveUninitialized: true,
resave: true,
// using store session on MongoDB using express-session + connect
store: new MongoStore({
url: config.urlMongo,
collection: 'sessions'
})
}));
// Init passport authentication
app.use(passport.initialize());
// persistent login sessions
app.use(passport.session());