Issue with Sitemap XML WordPress wp-sitemap.xml

I cannot replicate such an issue on my site. I don’t actually have over 2000 posts of any type, but I’ve reduced the posts per page count so I can get multiple sitemap pages. I don’t think it’s a core WP issue.

Your theme or one of your plugins is corrupting the query used to compile sitemap pages. It’s pretty much just a normal WP_Query posts query that code can easily alter, intentionally or not. This often happens when plugins use the default “paged” query var for their own purposes.

Eliminate possible sources of this corruption. Deactivate all plugins and switch to a twenty* default theme. Restore whatever module has added your news post type. Check your sitemap pages again. If there is still an issue, the module adding the news post type is the one responsible. If the issue is gone, reactivate your remaining modules, one at a time, until the issue returns.

Seek help through the dedicated support forum of the responsible module.

/wp-sitemap-posts-news-2.xml is loaded, but a 404 error is visible

So you can see the proper content, but the request returns a 404 status? That is very strange, This would indicate the wrong response header is being sent even though the request otherwise works. Somehow the query is being corrupted in a way I cannot explain. Since I cannot replicate this behavior on a my site, I can only guess at what might be the problem.

We’ve ruled out plugins and themes. There could still be a must-use plugin involved. It can be deactivated by renaming the /mu-plugins/ folder (in /wp-content/) If there is no such folder, you have no must-use plugins.

There could be something odd about the server configuration. A rule in .htaccess could cause problems for example. Or modSecurity could be interfering, although it normally returns 403 status, not 404.

It’s possible core WP became corrupted somehow, perhaps due to a faulty update. If you haven’t done so yet, update to the latest version. If you’re already there, try the Re-install button on the updates screen. TBH, I don’t fully trust the re-install button. For greater confidence I recommend doing a manual “update”, even though it’s really to the same version (from a freshly downloaded .zip).

I’m glad it’s fixed. I guess there’s no simple way to know which specific fix or optimization actually solved the problem.

When you have a spare moment, it’d be awesome if you left a review for the plugin. I don’t have any relation to the plugin, but it helps the WP community overall to review plugins that do good things for us.