Passport.authenticate custom callback inverts err and user arguments

Question

I'm developing a node server for user authentication with Passport.js and its Local Strategy.

About the /login part, here is my code :

router.get('/login', (req, res, next) => {
  passport.authenticate('local', (err, user, info) => {
    if(err) return next(err);
    if(!user) return res.send('User not found');
    req.logIn(user, (err) => {
      if(err) return next(err);
      console.log("coucou6");
      return res.send(user.email);
    })
  })(req, res, next)
});

But it doesn't work. When I log err, it shows me a user object :

[nodemon] starting `node app.js`
Server on port 9000
Connected to Pitch Masters database
{ _id: 5d70df248aac0e462fd55b83,
  email: 'coucou2@gmail.com',
  password:
   '$2a$10$w0PJny06QF6zINMXrBFiKuK5YWWxBneDqCAAa3pHzofFERXIiCm0S',
  __v: 0 }

And when I log user and info, I get undefined. So, naively, I tried to reverse err and user, but then I get :

Error: passport.initialize() middleware not in use
    at IncomingMessage.req.login.req.logIn (/Users/gabschemoul/Code/Professional/pitchmasters_webapp/server/node_modules/passport/lib/http/request.js:46:34)
    at passport.authenticate (/Users/gabschemoul/Code/Professional/pitchmasters_webapp/server/routes/auth.js:62:9)
    at Strategy.strategy.error (/Users/gabschemoul/Code/Professional/pitchmasters_webapp/server/node_modules/passport/lib/middleware/authenticate.js:353:18)
    at verified (/Users/gabschemoul/Code/Professional/pitchmasters_webapp/server/node_modules/passport-local/lib/strategy.js:81:28)
    at User.findOne.then (/Users/gabschemoul/Code/Professional/pitchmasters_webapp/server/config/passport.js:14:24)
    at process._tickCallback (internal/process/next_tick.js:68:7)

Do you manage to guess what could go wrong ? Do I need to share more code with you ?

Thanks a lot !