Failed to load map. Error contacting Google servers. This is probably an authentication issue

I search all days and I can't find the answer... everything is ready but google map still can't show on fragment with tab I check that I already turn on google map android v2 and right API_KEY I have no idea what happened! MainActivity.java: ``` public class MainActivity extends FragmentActivity implements ActionBar.TabListener { SectionsPagerAdapter mSectionsPagerAdapter; ViewPager mViewPager; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); String titles[] = { this.getString(R.string.title_around), this.getString(R.string.title_map), this.getString(R.string.title_favorite), this.getString(R.string.title_achievement), }; final ActionBar actionBar = getActionBar(); actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS); mSectionsPagerAdapter = new SectionsPagerAdapter( getSupportFragmentManager()); mViewPager = (ViewPager) findViewById(R.id.pager); mViewPager.setAdapter(mSectionsPagerAdapter); mViewPager .setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() { @Override public void onPageSelected(int position) { actionBar.setSelectedNavigationItem(position); } }); for (int i = 0; i < titles.length; i++) { actionBar.addTab(actionBar.newTab().setText(titles[i]) .setTabListener(this)); } } @Override public boolean onCreateOptionsMenu(Menu menu) { getMenuInflater().inflate(R.menu.main, menu); return true; } @Override public void onTabSelected(Tab tab, FragmentTransaction fragmentTransaction) { mViewPager.setCurrentItem(tab.getPosition()); } @Override public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) { } @Override public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) { } public class SectionsPagerAdapter extends FragmentPagerAdapter { public SectionsPagerAdapter(FragmentManager fm) { super(fm); } @Override public Fragment getItem(int position) { // TODO 在這邊決定哪個位置要給什麼 View（Fragment） Fragment fragment = null; // TODO 建議先在之前就初始化好 4 個 Fragment switch (position) { case 0: fragment = new AroundFragment(); break; case 1: fragment = new MapsFragment(); break; case 2: fragment = new FavoriteFragment(); break; case 3: fragment = new AchievementFragment(); break; default: break; } return fragment; } @Override public int getCount() { return 4; } @Override public CharSequence getPageTitle(int position) { // TODO 在這邊決定每一個 View 的 title switch (position) { case 0: return getString(R.string.title_around); case 1: return getString(R.string.title_map); case 2: return getString(R.string.title_favorite); case 3: return getString(R.string.title_achievement); } return null; } } } ``` MapsFragment.java: ``` public class MapsFragment extends Fragment{ static final LatLng NKUT = new LatLng(23.979548, 120.696745); private GoogleMap map; SupportMapFragment mMapFragment; public MapsFragment() { } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { View rootView = inflater.inflate(R.layout.map_fragment,container, false); map = ((SupportMapFragment)getFragmentManager().findFragmentById(R.id.map)).getMap(); mMapFragment = SupportMapFragment.newInstance(); FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction(); fragmentTransaction.add(R.id.map,mMapFragment); fragmentTransaction.commit(); return rootView; } } ``` Map_fragment.xml ``` <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context=".MainActivity" > <fragment android:id="@+id/map" android:layout_width="match_parent" android:layout_height="match_parent" class="com.google.android.gms.maps.SupportMapFragment" /> </RelativeLayout> ``` Manifest.xml: ``` <!-- Google Map --> <permission android:name="com.jertt.yummymap.permission.MAPS_RECEIVE" android:protectionLevel="signature"/> <uses-permission android:name="com.jertt.yummymap.permission.MAPS_RECEIVE"/> <uses-permission android:name="android.permission.INTERNET"/> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/> <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/> <!-- The following two permissions are not required to use Google Maps Android API v2, but are recommended. --> <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/> <!-- end --> <!-- Google Map API Key --> <meta-data android:name="com.google.android.maps.v2.API_KEY" android:value="key" /> <!-- end --> ``` Solution: I found the solution!!! If you use private keystore to apply API_KEY. You cannot upload and install application with eclipse. You need to upload .apk file to your device by yourself and install it! Thanks Tarsem and srikanth gr help!!