That URL is not a RSS feed. Double-check it.

Hi everyone,

I cant set my Last Acitivities RSS Feed into the flickr comment importer plugin. It keeps saying: “That URL is not a RSS feed. Double-check it.”

Here my url, whats wrong with that?!
https://api.flickr.com/services/feeds/activity.gne?user_id=9967634@N03&lang=de-de&format=atom