Why Rss feed widgets Not Refreshed!

Ive got a site: news.rodos-island.gr where i’ve installed WP Super Cache. Also in my other sites like this: gossip.rodos-island.gr. OK, Now the problem is that in the first site, the rss feed widgets (rss of the second site-gossip.rodos-island.gr/feed) is not refreshed!! It looks that it has not any rss new posts. I would like to ask what to do please. Should i disable the WP Super Cache in the first site? Or in the second? Any solution please,thanks