E:\project\nodejsdemo>node app.js

demo1 started on port 3000

E:\project\nodejsdemo\node_modules\mongoose\node_modules\mongodb\lib\server.js:228

        process.nextTick(function() { throw err; })

                                            ^

Error: connect ECONNREFUSED

    at exports._errnoException (util.js:746:11)

    at TCPConnectWrap.afterConnect [as oncomplete] (net.js:1010:19)