RSS feed not recognized

#1

I am looking to subscribe to this blog in Newsblur: https://access42.net/blog?lang=fr

The RSS feed in the page is https://access42.net/spip.php?page=backend

When I add either URL in Newsblur I get this error: “This address does not point to an RSS feed or a website with an RSS feed.”

This feed works on other RSS readers. I looked at it and did not find the issue. Could you have a look at what is wrong with this feed?

Thanks!