Nodejs api not accepting the POST method, error 405 - node.js

Question

I already search for existing question, but none of them worked for me.
I've simple nodejs methods, on my localhosts they work fine, but when I hosted them on a server (nginx), my post method gives error of 405 (not allowed), even though I've allowed CORS
Here is my server file
var http = require('http');
var mongo = require('mongodb');
var cors = require('cors')
var express = require('express');
var app = express();
app.use(cors());
var DB = 'mongodb://localhost:27017/ClientApp';
app.use(express.json());
const clientRoutes = require('./client');
const authRoutes = require('./auth');
app.get('/api/status', (request, response) => {
// console.log(request.body);
response.json({ status: ' Server Running' });
});
app.use('/', clientRoutes);
app.use('/', authRoutes);
app.listen(3000, (resp) => {
console.log('server listening at port number: ', 3000);
});
and here is the route that is not working
app.post('/api/register', (request, response) => {
console.log('Request body: ', request.body);
mongo.connect(DB, (error, client) => {
console.log('Connect to Database successfully');
const connectedDb = client.db('ClientApp');
data = request.body;
if (data.username) {
connectedDb.collection('Users').insertOne(data, (error) => {
if (error)
console.log('Error occured while registration')
else {
response.status(200).send({ status: 'Response Received Successfully', code: 200 })
console.log('User registered successfully!');
}
})
} else {
response.status(204).send({ status: 'Please include the user details', code: 204 })
}
})
});

Answer 1

I see you have your app's listening port set to 3000. You will need to verify in the nginx.conf file that is the port the traffic is being set to from the reverse proxy. Depending on how things are setup, there may be an environment variable set indicating which port the app should listen to. This variable is commonly called PORT.
If the PORT environment variable is being set you can change your code like so:
app.listen(process.env.PORT || 3000, (resp) => {
console.log('server listening at port number: ', 3000);
});
In case you're not aware, using process.env.PORT || 3000 will use the value process.env.PORT if it is set. If it is falsy then 3000 will be used.
For NGINX have a look at the nginx.conf at the server entries to determine how the reverse proxy is sending traffic to backend apps.