Then, validate your feed using the W3C Feed Validation Service, a free service that checks the syntax of Atom or RSS feeds.
If the feed is valid, go to http://www.netvibes.com/?reset_cache=1 to clear your Netvibes account cache
If the feed is invalid, that means something is formatted incorrectly. Contact your feed publisher
If your feed is completely missing (you'll usually get an 404 error), double-check the URL (ensure you spelled everything correctly)
When the feed takes a long time to load, please note that in order to preserve our quality of service, crawling is interrupted when there are more than 1,000 items in a single feed or when a feed does not respond after 10 seconds. It will be the same as if it was inaccessible.
If the feed requires a username and a password, double check with your feed publisher if something has changed.