Facebook Instant Articles RSS Feed Not Working - No Articles

So, I've been struggling with Facebook's instant RSS features article for several weeks now and I can't seem to get it to work. I followed the guidelines step by step: I added a meta tag fb:page

to our head :

<meta property="fb:pages" content="435703749965571" />

      

        
        
        
      

    

I am posting an rss feed as close as possible to the guidelines here: hokify.at/fb-articlefeed.rss

I've already talked to FB business support and so on, but no matter what I do, articles posted to the RSS feed don't show up in my backend. no errors or nothing, it just says "no instant articles created". I really have no idea about this. Can someone help and maybe point me in the right direction what is wrong with my feed ?

Thanks for a bunch in advance! best, P