I would like to add bit of extra information…
It seems like it is something to do with category.
I imported all the appdev contents prior to build the site and there are couple of category name like business, nature and Uncategorized. When I choose them as a category to post / publish or update post, there is no 404 error.
If I choose category name for example “Product” (slug name: product) for post, 404 error occurs when trying to view the single page. As I explained earlier blog page (view all post page) shows all the post (even post that uses category name “product”) but not single page…
Hope my writing makes sense.