reorder plugin menu position

Check if this solution (provided by @Syrehn) works: Reorder plugin items in the admin menu

Try taking just the name from the page admin link and see if it works. Something like this:

function custom_menu_order($menu_ord) {
if (!$menu_ord) return true;

return array(
    'index.php', // Dashboard
    'separator1', // First separator
    'edit.php', // Posts

    'pluginname2', // Take the name from the page menu admin.php?page=pluginname2

    'upload.php', // Media
    'edit.php?post_type=page', // Pages
    'edit-comments.php', // Comments

    'pluginname', // Take the name from the page menu admin.php?page=pluginname

);
}
add_filter('custom_menu_order', 'custom_menu_order'); // Activate custom_menu_order
add_filter('menu_order', 'custom_menu_order');

I would have made this a comment, but I can’t do that yet.