Error occured while trying to proxy to: http://localhost:4200/api/* - node.js

Question

I am running my Angular Project on npm start and expect it to listen simultaneously to port 3000 (that is suppose to listen automatically to anything that is in the api folder).
Anyway, it looks like it is trying to listen to the port, but it keeps catching an error for who knows what reason
Doing a node BLL.js directly to see if there is a JSON output works like a charm, but having the REST api work does not seem to work weirdly.
package.json
{
"name": "project-vas",
"version": "0.0.0",
"scripts": {
"ng": "ng",
"start": "ng serve --proxy-config proxyConfig.json",
"build": "ng build --env=prod",
"test": "ng test",
"lint": "ng lint",
"e2e": "ng e2e"
},
proxyConfig.json
{
"/api": {
"target": "http://localhost:3000",
"secure": false,
"changeOrigin": true
}
}
api/DBConnection.js
exports.config = function()
{
return config = {
user: 'username',
password: 'password',
server: 'localhost',
database: 'databaseName'
};
}
api/BLL.js
const express = require('express');
const path = require('path');
const sql = require('mssql');
const app = express();
const connection = require('./DBConnection');
let config = connection.config();
const port = process.env.PORT || 3000;
app.use(express.static(__dirname + '/dist/ProjectName/'));
app.get('/*', (require, res) => res.sendFile(path.join(__dirname)));
app.get('api/usertypes', function (req, res) {
sql.connect(config, function (err) {
if (err) { console.log(err); }
else {
var request = new sql.Request();
request.query('sp_GETUSERTYPES', function (err, recordset) {
if (err) {
console.log(err);
}
res.send(recordset);
});
}
});
});
environment.ts
export const environment = {
production: false,
api:"http://localhost:3000",
};
Just the expected Stored Procedure output in the shape of a JSON array.
But 'Error occured while trying to proxy to: localhost:4200/api/usertypes' keeps getting returned whenever I try to test it on Postman.