An unidentified error has occurred wordpress custom taxonomy/category

Question

I have create a custom category taxonomy in wordpress. And successfully created and display on wordpress admin.

Problems:

1. I tried to add a new category, but I need to refresh the page first to show the newly created category.

2. When I delete a category it shows that An unidentified error has occurred and the category is still on the list. I need to refresh the page so that the category will be removed.

here's my code

// hook into the init action and call create_schedule_taxonomies when it fires
add_action( 'init', 'create_schedule_taxonomies', 0 );

// create two taxonomies, genres and writers for the post type "book"
function create_schedule_taxonomies() {
    // Add new taxonomy, make it hierarchical (like categories)
    $labels = array(
        'name'              => _x( 'Categories', 'taxonomy general name' ),
        'singular_name'     => _x( 'Category', 'taxonomy singular name' ),
        'search_items'      => __( 'Search Category' ),
        'all_items'         => __( 'All Categories' ),
        'parent_item'       => __( 'Parent Category' ),
        'parent_item_colon' => __( 'Parent Category:' ),
        'edit_item'         => __( 'Edit Category' ),
        'update_item'       => __( 'Update Category' ),
        'add_new_item'      => __( 'Add New Category' ),
        'new_item_name'     => __( 'New Category' ),
        'menu_name'         => __( 'Categories' ),
        // more labels here...
    );

    $args = array(
        'hierarchical'      => true,
        'labels'            => $labels,
        'show_ui'           => true,
        'show_in_rest'      => true,
        'show_admin_column' => true,
        'query_var'         => true,
        'rewrite'           => array( 'slug' => 'schedule_category' ),
    );
    register_taxonomy( 'schedule_category', array( 'schedule' ), $args );
}

How can we solve that?

Answer 1

function create_schedule_taxonomies() {
 register_taxonomy(  
   'schedule_category',  //The name of the taxonomy. Name should be in slug form (must not contain capital letters or spaces). 
   'schedule' ,        //post type name
   array(  
       'hierarchical' => true,  
       'label' => 'schedule categories',  //Display name
       'query_var' => true,
       'rewrite' => array(
           'slug' => 'schedule_category', // This controls the base slug that will display before each term
           'with_front' => false // Don't display the category base before 
       )
   )     );            }  add_action( 'init', 'create_schedule_taxonomies' );

Answer 2

I faced the same problem in my theme.

Remove extra whitespace in php tag in functions.php file.

OR

Remove unwanted Plugins.