I wrote a basic map application, the one that an be easily instantiated with AndroidStudio. The only difference the fragment is loaded inside another custom layout.

```
package com.wayl.activities;

import android.os.Bundle;
import android.support.v4.app.FragmentManager;
import android.support.v7.app.AppCompatActivity;

import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

import com.wayl.R;

public class MapsActivity extends AppCompatActivity {

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

        FragmentManager myFragmentManager = getSupportFragmentManager();
        SupportMapFragment mapFragment = (SupportMapFragment) myFragmentManager.findFragmentById(R.id.map);
        GoogleMap mMap = mapFragment.getMap();

        // Add a marker in Sydney and move the camera
        LatLng sydney = new LatLng(-35, 152);
        mMap.addMarker(new MarkerOptions().position(sydney).title("Marker near Sidney"));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
    }
[...]

```

As said above, the app works perfectly in the AVD, but no way to make it work on a real device. It shows just an empty map placeholder, and **also the colourful Google logo is there**. But no markers, no grid, no buttons, nothing else.

Why I think it should work:

* Network, wifi, are ok, both on the phone as in the AVD
* [The OpenGL version shouldn't be a problem](https://stackoverflow.com/questions/28974313/google-map-showing-on-emulator-but-not-on-device), I'm running the apk both on a 
Galaxy Samsung S3, and on a Galaxy Note 4.
* I placed my fingerprints both for debug and release version retrieved with *keytool* and connected with my keystore, so [key it's OK](https://stackoverflow.com/questions/11414988/google-maps-not-showing-on-phone-but-works-on-emulator), you can also see [the reference image](https://i.stack.imgur.com/lrRyu.jpg), even if it said this is optional. I put both the base package and the package containing the Maps activity just for being sure.
* I waited enough time for [the app to fetch the location](https://stackoverflow.com/questions/24479225/google-maps-application-works-on-emulator-but-not-real-device), and for the fingerprint to propagate in case this would be needed.
* Manifest has all the correct permission to retrieve coarse and fine location (remember in the AVD everything works perfectly)

I already succeed in the past to develop a map on Android. I remember each time after 4 or 5 trial and errors on the frustrating process I could achieve it. This time I don't know what to do more. I'm exploting S.O. to understand where I am mistaking.