Accessing webservices from a website which is running behind a proxy

I am designing a website using ember and express over node. Its running in a server, say: SERVER_1. I have few webservices running in another server, say: SERVER_2. That is: website in SERVER_1 and webservices available in SERVER_2 SERVER_1 is behind a proxy server. And I am trying to access webservices from SERVER_1: ``` SERVER_1 =====[PROXY]===> SERVER_2 ``` When I make AJAX webservice calls from SERVER_1, I receive: ``` NetworkError: 500 Internal Server Error ``` However, I am able to retrieve values successfully through browser. Only through AJAX code, I am retrieving Network 500 error. Also for testing, I removed my proxy server setup: ``` SERVER_1 =====> SERVER_2 ``` and I was able to access all those web services successfully both via AJAX code and browser. If I have a proxy server in between them: ``` SERVER_1 =====[PROXY]===> SERVER_2 ``` I am getting -- NetworkError: 500 Internal Server Error I like to know the procedures to access third-party webservices from a website which is running behind a proxy server? Additional Info: Already to fix cross domain web-service access issue (website running in one server and webservices running in some other different servers with different ports), I am using http-proxy npm and my code is as follows: ``` var express = require('express'); var routes = require('./routes'); var http = require('http'); var path = require('path'); var httpProxy = require('http-proxy'); var endpoint = { host: 'IP_ADDRESS_WHERE_MY_WEBSERVICES_RUN', port: 80, prefix: '/api' } var proxy = new httpProxy.RoutingProxy(); var app = express(); app.set('port', process.env.PORT || 3000); app.set('views', path.join(__dirname, 'views')); app.set('view engine', 'ejs'); app.use(express.favicon()); app.use(express.logger('dev')); app.use(express.methodOverride()); app.use(express.cookieParser('xxxxx')); app.use(express.session()); app.use(app.router); app.use(express.static(path.join(__dirname, 'public'))); app.use(function(req, res) { if (req.url.indexOf(endpoint.prefix) === 0) { proxy.proxyRequest(req, res, endpoint); } }); app.use(express.bodyParser()); if ('development' == app.get('env')) { app.use(express.errorHandler()); } app.get('/', routes.index); http.createServer(app).listen(app.get('port'), function(){ console.log('Express server listening on port ' + app.get('port')); }); ``` My AJAX call: ``` $.ajax({ type: 'GET', async: false, url: 'API_URL', success: function (data) { alert('success'); }, failure: function(error){ alert('error'); } }); ``` Already I using http-proxy to handle all url's request. How can I configure my proxy server's IP address and port in the above code, so that I can access all these webservices successfully? Or is there some way to have my proxy configurations in AJAX call? Can anyone please guide me? Thank you