Sending email via mailgun

I am trying to add a mailgun contact form to my site using nodejs express and mailgun-js. But somehow I can't get it to work. My api key and domain are good as I tested them with sample code on mailgun-js official github page. So I am wondering if there is anything wrong with the following parts of the code. (routing and everything else works fine)

./models/mailer.js

            var api_key = 'xxxxxxx';
            var domain = 'xxxxxxxx';

            var Mailgun = require('mailgun-js');

            exports.sendOne = function (locals,callback) {

                console.log(locals);
                var mailgun = new Mailgun({apiKey: api_key,domain:domain});

                var data = {
              from: 'xxxxxx',
              to: 'myemail@hotmail.com',
              subject: 'Hello World',
              text: 'Testing some Mailgun awesomness!'
            };

                mailgun.message().send(data,function (err,body) {
                        if(err) return callback(err);
                        console.log('message sent');
                        callback(null,body);
                });
            };

      

        
        
        
      

    

./controllers/contactCtrl.js

    var mailer = require('../models/mailer');

    exports.contact = function (req,res,next) {
        res.render('contact');
    };


    exports.receiveMessage = function (req,res,next) {

            mailer.sendOne(req.body,function (err,body) {
                if(err) return next(err);
                console.log(body);
                res.send({message:'Your message has been successfully sent'});
            });

    };

      

        
        
        
      

    

Thank you so much:)