Axios isn't sending session data - node.js

Question

I've developed an app using React, Mongodb, Node, and Express and i'm using sessions for authentication. On the backend, I can successfully set a cookie a store a userID however when I try to make requests from the react app using axios, the userID session data is not sent.
This is my session config on the backend:
app.use(session({
name: SESS_NAME || "***",
secret: SESS_SECRET || "***",
saveUninitialized: false,
resave: false,
store: new MongoStore({
mongooseConnection: db,
collection: 'session',
ttl: parseInt(SESS_LIFETIME) / 1000 || (60 * 60 * 48) / 1000
}),
cookie: {
sameSite: true,
path: '/',
domain: APP_DOMAIN || 'localhost:4000',
secure: false, //NODE_ENV === 'production',
maxAge: parseInt(SESS_LIFETIME) || 60 * 60 * 48
}
}));
My cors is configured as follows:
app.use(function(req, res, next) {
res.header("Access-Control-Allow-Origin", "http://localhost:4000");
res.header("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
res.header("Access-Control-Allow-Credentials", true);
next();
});
const corsConfig = {
origin:['http://localhost:3000', 'http://localhost:4000' ],
methods:['GET','POST'],
credentials: true,
};
app.use(cors(corsConfig));
after logging in I set the userID in my user Routes, which I confirmed is set by console logging:
req.session.userId = user._id;
This is an example request from my react app
axios.get('/user/auth', { withCredentials: true })
.then(response => {
...
Note that my app is being served on the same domain - I'm using the node app to serve the react app. my folder structure is similar to the following
- APP PARENT FOLDER
-CLIENT //Whole react app
-MODELS
-ROUTES
-SERVER.JS
-PACKAGE.JSON
-NODE_MODULES
I have searched everywhere and tried everything I can think of... no luck. I would appreciate any help!
I've already checked articles on stack overflow and tried to implement the fixes but have had no luck. I've tried the following fixes:
// in my index.js file
axios.defaults.withCredentials = true;
and adding
{ withCredentials: true }
to all of my requests
When I take the userid created at login (ex: 5d6b5d2b09f7d1332543ba90) and manually plug this into the user Route on the backend then everything works fine.
When I console log the session on every request made by the react app it looks like this:
Session {
cookie:
{ path: '/',
_expires: 2019-09-05T05:38:09.657Z,
originalMaxAge: 172800,
httpOnly: true,
sameSite: true,
domain: 'localhost:4000',
secure: false },
}
When it should look like this:
Session {
cookie:
{ path: '/',
_expires: 2019-09-05T05:38:09.657Z,
originalMaxAge: 172800,
httpOnly: true,
sameSite: true,
domain: 'localhost:4000',
secure: false },
userId: 5d6b5c2b03f7d5532543ba90 }