How to display Custom Taxonomy under Custom Admin Menu?

Question

I have problem to display custom taxonomy under custom admin menu. Custom post types are displayed properly, but the taxonomy doesn't appear.

I added to custom post types: 'show_in_menu' => 'my-menu'

My Custom Menu

• Custom Post Type 1
• Custom Post Type 2
• Custom Post Type 3
• Custom Taxonomy that can be used by Post Type 1/2/3

What i need to do to display custom taxonomy?

UPDATE

Here's my code:

function create_custom_admin_menu() {
  add_menu_page(
    'My Menu',
    'My Menu',
    'read',
    'my-menu',
    '',
    'dashicons-admin-page',
    10
  );
}
add_action( 'admin_menu', 'create_custom_admin_menu' );


function create_custom_post_type_1() {
  $labels = array(
    'name' => _x( 'Custom Post 1' ),
    'singular_name' => _x( 'Custom Post 1' ),
    'menu_name' => __( 'Custom Post 1' ),
  );
  register_post_type( 'custom-post-type-1', array(
    'labels' => $labels,
    'has_archive' => false,
    'public' => true,
    'show_in_menu' => 'my-menu',
    'supports' => array( 'title', 'editor', 'auther', 'excerpt', 'custom-fields', 'thumbnail','comments' ),
    'taxonomies' => array( 'custom-taxonomy' ),
    'exclude_from_search' => false,
    'capability_type' => 'post',
    )
  );
}
add_action( 'init', 'create_custom_post_type_1' );


function register_custom_taxonomy() {
  $labels = array(
    'name' => _x( 'Custom Taxonomy'),
    'singular_name' => _x( 'Custom Taxonomy' ),
    'menu_name' => __( 'Custom Taxonomy' ),
  );
  register_taxonomy( 'custom-taxonomy', 'my-menu', array(
    'hierarchical' => true,
    'labels' => $labels,
    'query_var' => true,
    'show_admin_column' => true
  ) );
}
add_action( 'init', 'register_custom_taxonomy' );

UPDATE 2

I tried it all and nothing works:

register_taxonomy( 'custom-taxonomy', 'my-menu', [...]


register_taxonomy( 'custom-taxonomy', 'custom-post-type-1', [...]


register_taxonomy( 'custom-taxonomy', array('custom-post-type-1', 'custom-post-type-2', 'custom-post-type-3' ), [...]

Answer 1

You haven't properly registered the taxonomy for your post type. You register your post type like this:

register_post_type( 'custom-post-type-1',

Meaning that your post type is named custom-post-type-1. But when you register the taxonomy, you're registering it for a post type called my-menu"

register_taxonomy( 'custom-taxonomy', 'my-menu',

You need to register your taxonomy for your post type:

register_taxonomy( 'custom-taxonomy', 'custom-post-type-1',

Answer 2

I think that there is an issue with your plugins. That's why, custom taxonomy is not showing up.

Turn off all the plugins. Then enable them one at a time. In this way, you can find the defective one. You have to remove it and use an alternate option.