BlogReader Unknown Host error

package com.ysr.blogreader;

import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;

import android.app.ListActivity;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.widget.Toast;

public class MainListActivity extends ListActivity {

    protected String[] mBlogPostTitles;
    public static final int NUMBER_OF_POSTS = 20;
    public static final String TAG = MainListActivity.class.getSimpleName();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main_list);

        if(isNetworkAvaliable()){
            GetBlogPostsTask getBlogPostsTask = new GetBlogPostsTask();
            getBlogPostsTask.execute();         
        }else{
            Toast.makeText(this, "Network Unavailable!", Toast.LENGTH_LONG).show();
        }

        //Toast.makeText(this, getString(R.string.no_items), Toast.LENGTH_LONG).show();
    }


    private boolean isNetworkAvaliable() {
        ConnectivityManager manager = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
        NetworkInfo networkInfo= manager.getActiveNetworkInfo();

        boolean isAvailable = false;
        if(networkInfo != null && networkInfo.isConnected()){
            isAvailable = true;
        }

        return isAvailable;

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main_list, menu);
        return true;
    }

     private class GetBlogPostsTask extends AsyncTask<Object, Void, String> {

            @Override
            protected String doInBackground(Object... arg0) {
                int responseCode = -1;

                try {
                    URL blogFeedUrl = new URL("http://blog.teamtreehouse.com/api/get_recent_summary/?count=" + NUMBER_OF_POSTS);
                    HttpURLConnection connection = (HttpURLConnection) blogFeedUrl.openConnection();
                    connection.connect();

                    responseCode = connection.getResponseCode();
                    Log.i(TAG, "Code: " + responseCode);
                }
                catch (MalformedURLException e) {
                    Log.e(TAG, "URLException caught: "+e, e);
                }
                catch (IOException e) {
                    Log.e(TAG, "IOException caught: "+e, e);
                }
                catch (Exception e) {
                    Log.e(TAG, "Exception caught: "+e, e);
                }

                return "Code: " + responseCode;
            }

        }
}