Taxonomy term page going to 404

Question

Why are my hits for a taxonomy term page getting a 404 error?

I have taxonomy "source', registered in code through a plugin...

<?php
/**
 * Plugin Name: Context Taxonomy for Sources
 * Description: Register custom taxonomy for sources.
 * Version: 1.0.0
 * Author: Robert Andrews
 */




/**
 * ==============================================================================
 *                      REGISTER TAXONOMY
 * ==============================================================================
 */

if ( ! function_exists( 'register_taxonomy_source' ) ) {

function register_taxonomy_source() {

  $labels = array(
        'name'                       => _x( 'Sources', 'Taxonomy General Name', 'text_domain' ),
        'singular_name'              => _x( 'Source', 'Taxonomy Singular Name', 'text_domain' ),
        'menu_name'                  => __( 'Sources', 'text_domain' ),
        'all_items'                  => __( 'All Sources', 'text_domain' ),
        'parent_item'                => __( 'Parent Source', 'text_domain' ),
        'parent_item_colon'          => __( 'Parent Source:', 'text_domain' ),
        'new_item_name'              => __( 'New Source Name', 'text_domain' ),
        'add_new_item'               => __( 'Add New Source', 'text_domain' ),
        'edit_item'                  => __( 'Edit Source', 'text_domain' ),
        'update_item'                => __( 'Update Source', 'text_domain' ),
        'view_item'                  => __( 'View Source', 'text_domain' ),
        'separate_items_with_commas' => __( 'Separate Sources with commas', 'text_domain' ),
        'add_or_remove_items'        => __( 'Add or remove Source', 'text_domain' ),
        'choose_from_most_used'      => __( 'Choose from the most used', 'text_domain' ),
        'popular_items'              => __( 'Popular Source', 'text_domain' ),
        'search_items'               => __( 'Search Source', 'text_domain' ),
        'not_found'                  => __( 'Not Found', 'text_domain' ),
        'no_terms'                   => __( 'No Source', 'text_domain' ),
        'items_list'                 => __( 'Sources list', 'text_domain' ),
        'items_list_navigation'      => __( 'Sources list navigation', 'text_domain' ),
    );
    $rewrite = array(
        'slug'                       => 'source',
        'with_front'                 => true,
        'hierarchical'               => false,
    );
    $args = array(
        'labels'                     => $labels,
        'hierarchical'               => false,
        'public'                     => true,
    'single_value'               => false, // Use single-select radio button, only one Source per object
        'show_ui'                    => true,
        'show_admin_column'          => true,
        'show_in_nav_menus'          => true,
        'show_tagcloud'              => true,
        'rewrite'                    => $rewrite,
    );
    register_taxonomy(
        /* taxonomy name */         'source',
        /* attach to object */  array( 'quote','article','report','event', 'post' ),
        /* arguments */                 $args
    );

}
add_action( 'init', 'register_taxonomy_source', 0 );

}




?>

The taxonomy works in the back-end.

Now I am building out a theme, I want to see that a page like http://www.example.com/source/term-name works. But it doesn't.

My .htaccess file contained...

# BEGIN WordPress
<IfModule mod_rewrite.c>

RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]

# add a trailing slash to /wp-admin
RewriteRule ^wp-admin$ wp-admin/ [R=301,L]

RewriteCond %{REQUEST_FILENAME} -f [OR]
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^ - [L]
RewriteRule ^(wp-(content|admin|includes).*) $1 [L]
RewriteRule ^(.*\.php)$ $1 [L]
RewriteRule . index.php [L]
</IfModule>

# END WordPress

# Modified for Multisite https://www.namecheap.com/support/knowledgebase/article.aspx/9191/29/how-to-create-a-wildcard-subdomain-in-cpanel
# Previous here:
# RewriteEngine On
# RewriteBase /
# RewriteRule ^index\.php$ - [L]
# RewriteCond %{REQUEST_FILENAME} !-f
# RewriteCond %{REQUEST_FILENAME} !-d
# RewriteRule . /index.php [L]

I have just removed those parts. Before this, the 404 /source/term-name page was actually getting redirected to the homepage.

I have...

• Removed the above .htaccess portions.
• Clicked Save on the Permalinks page
• Added flush_rewrite_rules() and similar to my code.

Still it's coming up 404. I don't understand it.

One interesting thing to note... On my "Source" taxonomy listing in the back-end, when you open a taxonomy term page with the view link, I just saw each site URL is like http://www.example.com/blog/source/term-name - not http://www.example.com/source/term-name. It should be the latter. However, both variants fail 404.

On my Permalinks Settings page, "Common Settings" is set to "Custom Structure": /blog/%year%/%monthnum%/%day%/%postname%/ That may be where "blog" is coming from, but I still don't understand the 404.

I just removed "/blog/". Now the URL is http://www.example.com/source/term-name - but, still, that is 404.

Answer 1

Following @CraigWayne's suggestion to use Query Monitor...

Message: "Use of undefined constant term_name - assumed 'term_name'". Count: 1. Location: wp-content/themes/elegant/taxonomy-source.php:38. Caller: wp-includes/template-loader.php wp-includes/template-loader.php:74. Component: Core. >>>>> Line 38 in taxonomy-source.php included ""

it was objecting to term_name in my taxonomy-source theme file; I changed it to $term = get_queried_object(); followed by name; ?>

The takeaway for others experiencing a 404 taxonomy term template - it might be dodgy code within the template file.