OpenGraph erratic behaviour

Hi,

In Yoast configuration I have Facebook enabled with an App ID and an URL for a default Featured Image, but when I share post and pages, behaviour is erratic:

1) Most posts appear in Facebook with their own Featured Image, but some do not, neither the default Featured Image appears. In this case, Facebook warnings are the following:

Inferred Property
The ‘og:image’ property should be explicitly provided, even if a value can be inferred from other tags.

Object Missing a Required Value
Object at URL ‘http://inforoses.com/roses-tanca-campanya-lanc-denunciar-greuges-lestat-contra-catalunya/’ of type ‘website’ is invalid because a required property ‘og:title’ of type ‘string’ was not provided.

2) Not a single Page appears in Facebook with its Featured Image neither the default one. Facebook warnings are these:

Inferred Property
The ‘og:image’ property should be explicitly provided, even if a value can be inferred from other tags.

Inferred Property
The ‘og:url’ property should be explicitly provided, even if a value can be inferred from other tags.

Share App ID Missing
The ‘fb:app_id’ property should be explicitly provided, Specify the app ID so that stories shared to Facebook will be properly attributed to the app. Alternatively, app_id can be set in url when open the share dialog.

But the App ID has been introduced and saved and it works with other plugins!

I am probably misunderstanding something about the configuration.

Could somebody help?

Thank you very much!!