Vuforia, Android, no shadows on device, shadows in Unity project window

I am making AR app. I got shadows in Unity project window, but when I build an app there is no shadows. I am using Unity 4.6.0 Free version and I tested my app on Galaxy S3 and S5 (5.0). I got one directional light with hard shadow, medium quality, lightmapping(tried all) auto and render mode important. I changed quality setting Shadow distance to 37. I made plane(with texture and shader diffuse) under model to cast shadow on it. Thanks for any help.