--- a/base/univention-app-appliance/usr/sbin/univention-app-appliance	
+++ a/base/univention-app-appliance/usr/sbin/univention-app-appliance	
@@ -83,6 +83,7 @@ def print_status(message):
 
 def configure_portal(app):
        lo, po = udm_uldap.getMachineConnection()
+       udm_modules.update()
        module = udm_modules.get('settings/portal')
        result = module.lookup(None, lo, 'cn=domain', base=UCR['ldap/base'], scope='sub')
        if not result: