RSS Feed not showing posts

My client uses WordPress and I’m trying to get their rss to feed in another website (which uses the textpattern CMS platform with an rss feed plug-in). And the plug-in works for every other rss feed that I’ve tried, except for my client’s. The site in question is located at: https://vahomeschoolers.org/blog/ and their feed URL is: https://vahomeschoolers.org/blog/feed/.

My suspicion is that it’s not the plug-in, rather something within the WordPress system. Or, maybe there’s a better URL to use.

Has anyone had this problem before and have a solution?

Thanks much!