I thought it was working fine, had some security issues with the site recently and discovered a bunch of outbound links on the sitemap page to drug & loan sites!!! If this happened to you can fix it by disabling the plugin and deleting all related files to the sitemap. Make sure you change all passwords, etc. for users and remove sitemap url created from plugin too. From now on I think I'll stick with SEO Yoast plugin for site maps.