I am currently having a similar issue. I use DIVI Builder, and Yoast SEO. The sitemap index appears fine, and you can click and go to the categories and tags sitemaps, but the post and pages sitemaps return a 404. I have tried uninstalling yoast and reinstalling, but it does the same thing. I have checked to make sure our server has rewrite rules set, and it does.
What’s weird is that the Yoast sitemaps were all working when I installed it. I went through for SEO and changed permalinks, and now it’s broken. Any ideas on how to fix would be great!
