Help: Warnings That Should Be Fixed in Facebook Debugger

I just got a picture for this link: Tak tilfar niður,
and the image size is 1200x630 and is a png file.
But when I put the link on the Facebook debugger, Facebook says: Warnings That Should Be Fixed. Missing Properties. The following required properties are missing: og:url, fb:app_id

What should I do with this issue, which Facebook debugger says as are missing??

Thank you so much for helping me!