I am new with Zimbra and have some problems, hope someone can help me.

I just tried to add a new Feed in my inbox-folder, unfortunately it seems not to work properly. After adding the feed into my inbox-folder and click on the Feed-name, i can see the some feed(probably from the last 3 days), but i cannot get new one.
I dont have the button "Load Feeds" instead i still have the button "Receive Mails" , if i tried to get new Feed by clicking on "Receive Mails", the application just switch to the inbox-Folder without loading the new feeds.