CF cache show debain default page

I have a site that

  1. if I disable cache, it works
  2. as soon as I enable chache into dns, I got debian default page

The backend server is a Debian with only one vhost

Did you try purging the cache

I purged cache many times, whout any change.
Still Debian default page.
Very strange: I note a line of logs every time i get site’s home page, and Debian default page instead of HP
So, it seems that the page is not coming from cache
I aam very confused