With all the new features in the latest 5.2 release of Sitefinity, it’s easy to almost miss Sitefinity Lightning. And after finally taking the time to play with it today, you surely do not want to miss it!
When you create a blog in Sitefinity, you must also assign it a Default Page, which is the page that contains the BlogPosts widget for displaying the full Details View of a post.
If you delete this page, move the BlogPosts widget to another page, or modify this relationship in any other way, you must make sure to update the settings for your blog so that it always points to the correct page. Otherwise, Sitefinity will have no way of knowing where your blog posts are located.