Recently, I was informed through Google's Webmaster tools that my posts sitemap file (http://technicallyeasy.net/post-sitemap.xml) is blank. All the other sitemaps contain data (page-sitemap.xml, category-sitemap.xml, post_tag-sitemap.xml) and the main sitemap_index.xml file is working properly.
I tried to get the posts sitemap file to regenerate, but it remains blank (I tried to download the file to see that it was, in fact, blank).
Is there a way to find out why the posts sitemap couldn't be created properly?
WordPress version: 3.4.2
WordPress SEO version: 18.104.22.168