Internal server error when deploying express using serverless

**[Nothing like stupid or useless questions we all learn here]** I'm facing a problem that I really can't solve for days, I'm trying to use serverless to get my express app The program deploys to aws but when i try to access the endpoint i get this error

{"message": "Internal server error"}

I can't really figure out the problem also looked at other similar questions but nothing worked

Here is my serverless.yml

    service: my-express-application

provider:
  name: aws
  runtime: nodejs14.x
  stage: dev
  region: us-east-1

functions:
  app:
    handler: app.handler
    events:
      - http: ANY /
      - http: 'ANY /{proxy+}'

Here is my app.js

const express = require("express");
const cookieSession = require("cookie-session");
const passport = require("passport");
const serverless = require('serverless-http');
const authRoutes = require("./routes/auth");
const userRoute = require("./routes/user/postUser")
const planRoute =require("./routes/user/main")
const profileRoutes = require("./routes/profile");
const passportSetup = require("./config/passport-setup");
const mongoose = require("mongoose");
const keys = require("./config/keys");
const activitiesRoutes = require("./routes/activity");
const app = express();
const bodyParser = require("body-parser");
const router = express.Router();
const AWS = require("aws-sdk");
AWS.config.update({
    region: "us-east-1",
});
var docClient = new AWS.DynamoDB.DocumentClient();

// set view engine
app.set("view engine", "ejs");

// set up session cookies
app.use(
    cookieSession({
        maxAge: 24 * 60 * 60 * 1000,
        keys: [keys.session.cookieKey],
    })
);

// initialize passport
 app.use(passport.initialize());
 app.use(passport.session());

// connect to mongodb
mongoose.connect(keys.mongodb.dbURI, () => {
    console.log("connected to mongodb");
});

// set up routes
app.use("/plan",planRoute);
 app.use("/auth", authRoutes);
app.use("/auth", activitiesRoutes);
app.use("/profile", profileRoutes);
app.use("/uSer", userRoute);

//Here we are configuring express to use body-parser as middle-ware.
app.use(bodyParser.urlencoded({ extended: false }));
app.use(bodyParser.json());

// create home route
app.get("/", (req, res) => {
    res.render("home", { user: req.user });
});
// app.get('/hi', function (req, res) {
//     res.send('Hello World!')
// })



app.listen(3000, () => {
    console.log("app now listening for requests on port 3000");
});
module.exports = serverless(app);