How to fix "TypeError: Cannot read property 'body' of undefined' in an expressjs REST API"

I'm setting up a REST API using Express, I ended up defining some endpoints and methods thats works, when suddenly appears an error: "TypeError : Cannot read property 'body' of undefined"

I'm fairly new to JS and i'm trying to build a webapp using mongodb, express and react.

I've been following some guides (this one in particular because it also implements JWT : https://www.toptal.com/nodejs/secure-rest-api-in-nodejs)

I have managed to build all the users methods for basic CRUD operations and have exposed them. Everything works fine, then I tried to add the Auth process with middlewares, and the error happened.

I looked for the answer, most commonly the error was due to body-parser being called after the routes. But in my case, I call the auth route just before the user route which works fine.

Here is my git repo for more details : https://github.com/pidanou/btb_api

const config = require("./config/env.config");

const express = require("express");
const bodyParser = require("body-parser");
const app = express();

const authRouter = require("./routes/auth.routes");
const userRouter = require("./routes/users.routes");

app.use(function(req,res,next){
    res.header('Access-Control-Allow-Origin', '*');
    res.header('Access-Control-Allow-Credentials', 'true');
    res.header('Access-Control-Allow-Methods', 
'GET,HEAD,PUT,PATCH,POST,DELETE');
    res.header('Access-Control-Expose-Headers', 'Content-Length');
    res.header('Access-Control-Allow-Headers', 'Accept, Authorization, 
Content-Type, X-Requested-With, Range');
    if (req.method === 'OPTIONS') {
        return res.send(200);
    } else {
        return next();
    }
});

app.use(bodyParser.json());
app.use(bodyParser.urlencoded({extended:true}));

authRouter.authRoutesConfig(app);
userRouter.userRoutesConfig(app);

app.listen(config.port, () => console.log(`Listening on port 
${config.port}`));

Code for the authRoute:

const verifyUserMiddle = require("../middlewares/verify.user.middle");
const authController = require("../controllers/auth.controller");

exports.authRoutesConfig = function (app) {

    app.post('/auth', [
        verifyUserMiddle.hasAuthValidFields(),
        verifyUserMiddle.isPasswordAndUserMatch(),
        authController.login()
    ])

}

Code for the controller:

const jwtSecret = require('../config/env.config').jwt_secret,
    jwt = require("jsonwebtoken");
const cyrpto = require("crypto");

exports.login = (req, res) => {

    try {
        let refreshId = req.body.userId + jwtSecret;
        let salt = crypto.randomBytes(16).toString("base64");
        let hash = cyrpto.createHmac("sha512", 
salt).update(refreshId).digest("base64");
        req.body.refreshKey = salt;
        let token = jwt.sign(req.body, jwtSecret);
        let b = new Buffer(hash);
        let refresh_token = b.toString("base64");
        res.status(201).send({accessToken: token, refresh_token: 
refresh_token});
    }catch(err){
        res.status(500).send({errors: err});
    }

} 

Since the user part worked fine, I thought the auth would too, but it didn't. It seems that the middleware is called before the body-parser. The error happens first in the middleware.