Status: 500 Internal Server Error While running Post - node.js

Question

I want to create an ESN and save it in my database
I'm using Nodejs and Mongodb
you can find the model, route and controller that I have created, what I want is a simple POST API to add an ESN to my data base.
Models
const mongoose = require("mongoose");
const Schema = mongoose.Schema;
const esnSchema = new Schema({
esnName: {
type: String,
required: true,
},
esnEmail: {
type: String,
required: true,
},
esnLogo: {
data: Buffer,
contentType: String,
required: false,
}
})
module.exports = mongoose.model("Esn",esnSchema);
Controllers
const Esn = require('../models/esn');
// create new ESN
const createEsn = async (req, res) => {
if (!req.body.esnName) {
res.status(400).send({ message: "Content can not be empty!" });
return;
}
const esn = new Esn({
esnName: req.body.esnName,
esnEmail: req.body.esnEmail,
esnLogo: req.body.esnLogo
});
// Save Esn in the database
esn
.save(esn)
.then(data => {
res.send(data);
})
.catch(err => {
res.status(500).send({
message:
err.message || "Some error occurred while creating the esn"
});
});
};
module.exports = {
createEsn
};
Routes
const mongoose = require("mongoose");
const Schema = mongoose.Schema;
const esnSchema = new Schema({
esnName: {
type: String,
required: true,
},
esnEmail: {
type: String,
required: true,
},
esnLogo: {
data: Buffer,
contentType: String,
required: false,
}
})
module.exports = mongoose.model("Esn",esnSchema);
index.js
const express = require('express'),
cors = require('cors'),
swaggerUi = require('swagger-ui-express'),
swaggerDocument = require('./docs/swagger.json');
const Mongo = require('mongodb');
const { default: mongoose } = require('mongoose');
const mainRoutes = require('./routes/esn')
const app = express();
var url = "mongodb://127.0.0.1:27017/";
var databasename = "skills";
Mongo.MongoClient.connect(url).then((client) => {
console.log('Database connected');
const connect = client.db(databasename);
//const collection = connect.createCollection("esn");
console.log('Database: ', connect);
}).catch((err) => {
// Handling the error
console.log(err.Message);
})
app.use(cors());
app.use(express.json());
app.listen(3000, () => {
console.log('Listening on port 3000!');
});
app.get('/', (req, res) => {
res.send('Hello World');
});
app.use('/api/', mainRoutes);
app.use('/api-docs', swaggerUi.serve, swaggerUi.setup(swaggerDocument));
I expected to save an esn in the database but I have this error
enter image description here