c# - TweetSharp Windows Phone NotFound -

i trying extend app include twitter user timeline functionality. using twitter api v1 , fetched user timeline properly. since api 1.1 deprecated, have been using tweetsharp.

however code runs on windows phone 7 , 8 emulators, windows phone 8 device fails on windows phone 7.1 lumia 710 device notfound exception.

the following code:-

twitterservice service = new twitterservice(_consumerkey, _consumersecret); service.authenticatewith(_accesstoken, _accesstokensecret);  listtweetsonusertimelineoptions listtweetsonusertimelineoptions = new listtweetsonusertimelineoptions(); listtweetsonusertimelineoptions.screenname = "twitter"; service.listtweetsonusertimeline(listtweetsonusertimelineoptions, (statuses, response) => {      if (response.statuscode == httpstatuscode.ok)// getting status code notfound      {          foreach (var status in statuses)          {             twitterstatus tweet = status;             //dispatcher.begininvoke(() => tweets.items.add(tweet));             debug.writeline(tweet.text);          }      }      else      {          throw new exception(response.statuscode.tostring());      } });