posts' pictures and messages dont show up when being shared on facebook

Hi,
I don’t know what is wrong with our website, but when I share posts from Information category on facebook, it doesn’t show the post’s picture and the excerpt of the post but only shows the website’s name and a weird thumbnail. It doesn’t happen like that when I share posts from other categories or pages on facebook. The error doesn’t happen when I share them on google plus either.
I don’t see the excerpt part show up on the post/page composing part either.
Can anyone help?
the error happens at this cat: https://www.noricac.com/category/information/
while it performs well at other cats for expl: https://www.noricac.com/category/events/
Thank you in advance for your help.