Addmedia not working – Twentyfourteen

Hello

For some reason, when I click AddMedia button to insert an image from the media library, it says its attached to the post, but doesn’t appear in the post. Just the title and a blank post. Everything was working beautifully, I changed to grid format under customize and set featured image for posts of interest, tagged with ‘Home’ to have them all showing up on first view, but now i can’t add media to posts ‘normally’ within the post, just stopped. I haven’t installed anything.. does anyone know what could be wrong or is this a design flaw of Twentyfourteen when using grid?

kind regards