Did the Yoast SEO plugin submit sitemap automatically?
 

Please i am new to this

The basic idea behind the rebuild of the XML sitemap functionality was simple: XML sitemaps needed to be more scalable, have a better API and cause less issues. Most of the issues were caused by two causes:

the fact that I was writing XML sitemaps to disk as static files;
the fact that I tried to generate one huge sitemap to catch everything.
Both of these were not really design decisions, just how it “turned out” when I had built the functionality and they turned out to be stupid. So, with the help of the incredibly talented Jon Cave, a WordPress core dev from the UK, the XML sitemap functionality has been rebuilt. It now has an index sitemap file that points to several sitemaps, one for each post type and taxonomy.