Ember.js Failed to validate oauth signature and token

[sohaibahmed]

var consumerSecret = ‘key’;
var encodedSignature = oauthSignature.generate(httpMethod, URL, parameters, consumerSecret);
var callback = encodeURIComponent(‘http://127.0.0.1:3000/#/loginlotwitter’, ‘UTF-8’);
var consumerkey = encodeURIComponent(‘key’, ‘UTF-8’);
var oauthNonce = encodeURIComponent(‘kllo9940pd9333jh’, ‘UTF-8’);

var Authorizationheader = {
“Authorization”: ‘OAuth oauth_callback=’+ callback +’, oauth_consumer_key=’+ consumerkey +’, oauth_nonce=’+ oauthNonce +’, oauth_signature=’+ encodedSignature +’, oauth_signature_method=“HMAC-SHA1”, oauth_timestamp=“1191242096”, oauth_version=“1.0”’
};

Ember.$.ajax({

            url:         'https://api.twitter.com/oauth/request_token',
            type:        httpMethod,
            contentType: "jsonp",
            contentType: 'application/x-www-form-urlencoded',
            //headers: Authorizationheader,
            beforeSend: function (xhr) {
                xhr.setRequestHeader("Authorization", 
                    'OAuth oauth_callback='+ callback +', oauth_consumer_key='+ consumerkey +', oauth_nonce='+ oauthNonce +', oauth_signature='+ encodedSignature +', oauth_signature_method="HMAC-SHA1", oauth_timestamp="1191242096", oauth_version="1.0"');
            },

        }).then(function(response) {
        	console.log('Successed');
        	console.log(response);
            resolve (response);
        }, function(xhr, status, error) {
            console.log(error);
            console.log('In Error');
            reject(error);
        });

Whats wrong in my code. every time I get Failed to validate oauth signature and token error.