Suseika

Same here. Why isn’t it working? Is this a sort of promotion of Modern Tribe’s non-free plugin with the same functionality?

I found out the solution and it worked perfectly for me, but I’m not sure that this is the right way. This link helped me a lot: https://www.wpbeginner.com/wp-themes/how-to-add-custom-items-to-specific-wordpress-menus/ I added this code in the template’s header.php before calling wp_nav_menu():

add_filter( 'wp_nav_menu_items', 'your_custom_menu_item', 10, 2 );
function your_custom_menu_item ( $items, $args ) {
    // Here goes anything you wish, it just has to be concatenated with $items variable.
    $items .= '<li><a href="'.get_post_meta(get_the_ID(), "foreignlink", true).'">Read this in Zorblaxian</a></li>';

    return $items;
}