bottom navigation bar color not changing

[ganhuilin015]

<com.etebarian.meowbottomnavigation.MeowBottomNavigation android:id="@+id/bottomNavigation" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_gravity="bottom" app:mbn_backgroundBottomColor="@color/purple_200" app:mbn_circleColor="@color/purple_200" app:mbn_countBackgroundColor="@color/light_blue" app:mbn_defaultIconColor="@color/purple_700" app:mbn_rippleColor="#2f424242" app:mbn_selectedIconColor="#3c415e" app:mbn_shadowColor="#1f212121" />

    From what I learn from the meow's video, changing the backgroundBottomColor should change the main bar color, but mine stays white. Any idea why?