og:image problem

Social preview is okay but new entry published in Facebook does not display og: image.

From Facebook debugger:
Warnings That Should Be Fixed
og:image could not be downloaded or is too small
Original image is near1920x1080 pix, resized by NGFB to 600x

In the same debugger, below:
Meta Tag <meta property=”og:image” content=”http://uruguaydesdeloalto.com/wp-content/uploads/2015/06/Screen-Shot-2015-02-08-at-19.57.37-600×315.jpg&#8221; />
Meta Tag <meta property=”og:image:width” content=”600″ />
Meta Tag <meta property=”og:image:height” content=”315″ />
And the right small thumbnail is displayed as og:image preview.

I don’t get how to correct that.
Thanks

https://ww.wp.xz.cn/plugins/nextgen-facebook/