There are two ways to refer to a resource in an Atom feed.
<uri/> element.<link/> element.So for example if you are using Rails' atom_feed helper, author blocks should look like:
entry.author do |author|
author.name 'Andy Stewart'
author.uri 'http://airbladesoftware.com'
end
The helper will generate <link/> elements whenever you use the :url or :root_url options.
You can validate your Atom feeds with the Feed Validator. Your feed needs to be publicly available to use the web version of the validator. Alternatively you can run the validator locally if you have Python.