General help

Hello Harmony - just to say I deleted your two posts in the Teaching with Moodle forum as they were duplicates of this post so unnecessary. I suggest you look (or if you are not an admin, ask your admin) at Site administration>Plugins>Enrolment/Self enrolment and see if "Require enrolment key" is enabled - that means that even if you remove the key as a teacher, a key will still be required as it is a site thing.