@rost I think there is a bug in our migration script. If you open /app/data/moodle/config.php, there will be a line $CFG->auth = 'ldap'; . Can you delete that line and try if it works after that? You will have to refresh the browser page.
Also, the LDAP details you see pre-filled are the Cloudron LDAP (172.18.x.x is the internal server/docker network). If you want to disable LDAP, please start afresh. We only support setting the LDAP flag at install time. It cannot be changed post installation (this is a limitation across all apps at this moment).