Error and Warnings

I’m testing out your plugin and it seems that it may fit the bill. However, on the debug I get this error message and warning:

Meta Tags In Body Your page has meta tags in the body instead of the head. This may be because your HTML was malformed and they fell lower in the parse tree.
Please fix this in order for the tags to be usable.
Notice
Warnings That Should Be Fixed
Inferred Property The ‘og:url’ property should be explicitly provided, even if a value can be inferred from other tags.
Inferred Property The ‘og:title’ property should be explicitly provided, even if a value can be inferred from other tags.
Inferred Property The ‘og:description’ property should be explicitly provided, even if a value can be inferred from other tags.
Inferred Property The ‘og:image’ property should be explicitly provided, even if a value can be inferred from other tags.”

On the first test post I added an image in the custom field and Facebook is picking it up – but I do not understand the error message and warnings and what I should be doing about them.

The post that I put in debug is:

https://wordpress.org/plugins/wonderm00ns-simple-facebook-open-graph-tags/