The error appeared only during the last week. I am confused as og: type "product" is not an ordinary og: type!
What has changed recently, what causes this?
Yep, Facebook is now starting to implement the Open Graph protocol. And in accordance with this, you did not specify objects in your application, respectively. Remove the og: or shortcut or add an object to the application definition on the Open Graph tab (https://developers.facebook.com/apps/{your app id} / opengraph)
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