Facebook Object Debugger: property 'og:url' could not be parsed as type 'url'

You should have scheme in front of og:url content (like http:// or https:// ), or this isn't URL.

In your specific case you should replace www.21dads.com/testobject with http://www.21dads.com/testobject

Roundup / checklist of possible issues to check for:

• Make sure your meta tag matches http:// or https:// in the URL.
• Make sure your meta tag matches www or non-www in the URL.
• (Sidenote: You should pick one combo of http/https www/non-www and redirect all of your traffic to that URL anyways, and make sure that matches your og:url meta tag)
• Check for whitespace before or after the URL
• Check for a trailing slash forced by Facebook that may not be in your meta tag
• Check for duplicated "og:url" meta tags
• Check that your URL is publicly available (you can't use the online debugger successfully for a localhost install - check it once you're on a staging or production site that's publicly available). Double check that you're not on a password-protected or IP address restricted environment.
• Check your spelling - is the URL really correct?
• Scrape the URL again. If you fixed it, you need to re-scrape, not just try again.

You can try to use this https://developers.facebook.com/tools/debug/og/object/ for see what is exactly scrapped. Anyway facebook say they are using open graph, but a lot of personnals test seems to say they don't.