Publicize post do not work anymore

Hello, I am the owner of the site https://www.euromusica.org, hosted by web4web, an italian hosting site.
My posts are setted to be published automatically on my facebook site page, on twitter and other social medias. But there are some day this publicizing do not work anymore. (error code: -10520)

More, when i try to share manually on facebook page, the preview don’t work and whatever kind of photo I use, don’t work on the facebook page. Tried also with debugger, is the same. Can you help me please?