Login form doesn’t show (shortcode)

I’m using the shortcode [ultimatemember form_id="9"] on my login page, but nothing shows up. Weirdly enough, when I’m logged in, I do see some stuff (profile picture, link to account and link to logout). When I view to source code I see that the shortcode is only outputting this:

<style type="text/css">
.um-9.um {
	max-width: 450px;
}</style>

I really don’t understand why my login form isn’t showing up. My pages are all set correctly in de plugin settings.