Can't get bookmark preview of cloudflare page

Hi,
If i share any link in the blog i get a instant preview as a bookmark. However we have a page which is hosted on cloudflare and that link does not work. To explain further we have a cms installed on our server which is rendered to static site. this static site than is hosted on cloudflare. however, if i share the cms page it works, if i share the cloudflare page it doesn’t. all the og metas are set exactly the same. the console shows a 422 error when i add the link to the post as a bookmark.