Why does not RSS client's update on my RSS post's?

Hello guys!

I have created a RSS service on a site. The url to be added to the client looks like:
http://jbossas-xxx.rhcloud.com/xxx.xml

The RSS service produce this xml:

<rss version="2.0">
<channel>
<title>News from xxx</title>
<link>http://jbossas-xxx.rhcloud.com</link>
<description>
This is the news channel from house 4.
</description>
<language>sv</language>
<pubDate>Fri, 03 Oct 2014 21:50:54 +0200</pubDate>
<item>
<title>Test 2</title>
<description>Testmessage 2</description>
<link>http://jbossas-xxx.rhcloud.com</link>
<author>Owner of house 4</author>
<guid>http://jbossas-xxx.rhcloud.com</guid>
</item>
</channel>
</rss>

In my RSS clients I have add/follow the url above:
http://jbossas-xxx.rhcloud.com/xxx.xml

I use these clients:
FeedDemon (should check for new posts every five minutes)
Feeder (plugin for chrome) (should check for new posts every two minutes)

Both clients read the a first post when I add/follow the url from beginning. But if I post a new post at the same url, the clients do not notify me about the update.

Do you guys see anything strange that would make client's that they would not recognize any new post? 

Best regards
Fredrik