WordPress SubMenu Page sufficient permissions

Why I always keep getting "You do not have sufficient permissions to access this page."?

It works for menu item, but I get above error on submenu page. Please help.

add_action('admin_menu', 'WPTestPlugin_add_global_custom_options');
function WPTestPlugin_add_global_custom_options()
{
    add_menu_page( 'WPTestPlugin', 'WPTestPlugin', 'manage_options', 'WPTestPlugin-options', 'WPTestPlugin_global_custom_options' );
    add_submenu_page( 'WPTestPlugin-options', "WPTestPlugin Dashboard", "Dashboard", 'manage_options', 'WPTestPlugin-dashboard', "WPTestPluginDashboard");

}