The type attribute in the app:collection/atom:title element cannot be arbitrary text.

Currently, in the AtomPub Service Document, the app:collection/atom:title element contains an English description of the collection. This is not allowed by AtomPub. This type attribute should either be one of "text", "xml" etc. or just removed from the service document.

Reference: http://www.atomenabled.org/developers/syndication/atom-format-spec.php#rfc.section.3.1.1