Google Webmaster Tools say "We do not detect any structured data on your site"

After you submit your video sitemap to Google Webmaster tools, sometimes you may get the message: "We do not detect any structured data on your site."

This usually refers to the homepage of a site (not the entire site).

To verify if Google recognizes the structured data on a specific post or page on your site, you can use the free Google structured data testing tool.

Your post that has a video will show the "video object" attribute. You may need to scroll down a little to see the code.