shortcode not rendering

Hello Catch Everest Theme! First of all thank you very much for your theme. I learned a lot about WordPress from your code. My problem is, that a shortcode is not rendering: [display-posts category="Projekte" posts_per_page="10"] According to the Wordpress documentation (Codex) this should be one of the default shortcodes. But instead of a list of pages, I only see the unrendered shortcode in my page: www.doogie.de/projekte I already disabled all plugins and made sure that the shortcode is not wrapped in paragraphs. What else can I check?