Google map Markers not showing

Here I am again.

My application has two API keys. (Google maps) A debug and another Realease.

In debug the map opens showing my markers perfectly. When I change the key, and I generate the APK, the map opens ... but my markers do not appear ....

I have gotten both keys correctly as send the tutorials. Below is my code

    MapFragment mapFrag = (MapFragment)FragmentManager.FindFragmentById (Resource.Id.map);
                GoogleMap map = mapFrag.Map;

                if (map != null && Entregas != null) {

                    foreach (Delivery delivery in Entregas) {

                        LatLng point = new LatLng (float.Parse (delivery.PickUpAddress.Latitude), float.Parse (delivery.PickUpAddress.Longitude));

                        // The GoogleMap object is ready to go.
                        MarkerOptions marker = new MarkerOptions ();
                        marker.SetPosition (point);
                        marker.SetTitle (delivery.Status);
                        marker.SetSnippet (delivery.ToString ());
                        marker.InvokeIcon (BitmapDescriptorFactory.FromResource (Resource.Drawable.caixa));
                        map.AddMarker (marker);

                    }

                    map.SetInfoWindowAdapter (new CustomMarkerPopupAdapter (LayoutInflater));
                    map.InfoWindowClick += MapOnInfoWindowClick;
                    map.MapClick += HandleMapClick;
                    map.MarkerClick += HandleMarkerClick;

                }

What the hell could it be?