Google Search Console: 404 on post sitemap

Hello,

I am using the XML sitemap functionality. The main sitemap is here: http://www.catalystrtw.com/sitemap_index.xml

The main sitemap is being crawled with no issue. Same with the Pages sitemap, which is located here: http://www.catalystrtw.com/page-sitemap.xml

The problem is that the Posts sitemap is giving me an error in Search Console. It’s located here, and can be loaded with no problem in my browser: http://www.catalystrtw.com/post-sitemap.xml

This is the error I get for the Post Sitemap in Search Console:

We encountered an error while trying to access your Sitemap. Please ensure your Sitemap follows our guidelines and can be accessed at the location you provided and then resubmit.

Example: General HTTP error: 404 not found
Sitemap: http://www.catalystrtw.com/post-sitemap.xml
HTTP Error: 404

I don’t understand why the Posts sitemap is producing an error in Search Console when it is displaying like the other two sitemaps in my browser.

Anyone have a similar issue or an idea how to fix this?

Thank you!

https://wordpress.org/plugins/wordpress-seo/