Missing atom:link with rel="self"

atom:feed elements SHOULD contain one atom:link element with a rel attribute value of "self". This is the preferred URI for retrieving Atom Feed Documents representing this Atom feed.

This value is important in a number of subscription scenarios where often times the feed aggregator only has access to the content of the feed and not the location from which the feed was fetched.

Insert a fully qualified link to your feed using rel="self".