Yoast category sitemap 404 caused by plugin

Hello! I’m using this plugin on the above site but it seems to be causing a problem with the “category” sitemap generated by Yoast. Any ideas why this is and how I can fix it? I’m guessing it’s to do with the “category” name being used by the plugin but I’m unable to change this.

Thanks!

The page I need help with: [log in to see the link]