RSS Feed added to my blog, not getting updated

Just today I began using the RSS Feed widget within my blog, to show up the feed from another site. For some reason after showing up it’s not getting updated (new things aren’t showing up). If I manually check the feed (by using the URL) it does have new stuff in there.

At first the issue I had was the feed not showing up at all, but it was because I had wp-cache. With this problem I disabled and deleted anything related to the plugin, and still, I can’t get the feed to update.