False url sitemap-index.xml

Manage your sitemaps with a sitemap index

If you have a sitemap that exceeds the size limits, you'll need to split up your large sitemap into multiple sitemaps such that each new sitemap is below the size limit. Once you've split up your sitemap, you can use a sitemap index file as a way to submit many sitemaps at once.

Sitemap index best practices

The XML format of a sitemap index file is very similar to the XML format of a sitemap file, and it's defined by the Sitemap Protocol. This means that all the sitemap requirements apply to sitemap index files also.

The referenced sitemaps must be hosted on the same site as your sitemap index file. This requirement is waived if you set up cross-site submission.

Sitemaps that are referenced in the sitemap index file must be in the same directory as the sitemap index file, or lower in the site hierarchy. For example, if the sitemap index file is at https://example.com/public/sitemap_index.xml, it can only contain sitemaps that are in the same or deeper directory, like https://example.com/public/shared/....

You can submit up to 500 sitemap index files for each site in your Search Console account. 

Welcome, ./assets/includes/functions_three.php

$sitemap->createSitemapIndex

Line 5283

$sitemap->createSitemapIndex($site . '/xml/', 'Today');

Remove /xml/ change to /

So like this

$sitemap->createSitemapIndex($site . '/', 'Today');