This is a Delivery Status Notification (DSN).

I was unable to deliver your message to
azummo-6oHk9+gzq0RsJHzoak81lQ@public.gmane.org

I said 
  RCPT TO:<azummo-6oHk9+gzq0Q+jrR7i3vcgg@public.gmane.org>

And they gave me the error;
  550 sorry, no mailbox here by that name (#5.1.1 - chkusr)