If you have not added the support Screen tag or compatible-screen tag in your manifest (must not use both together) i would suggest you to add support screen tag in your androidManifest.xml. this is how you can do it.
<supports-screens android:anyDensity="true" android:smallScreens="true" android:normalScreens="true" android:largeScreens="true" android:xlargeScreens="true"/>