You only need the enrolment key when you access the course for the first time. Once you have entered the key, you are enrolled and you no longer need it. However, it is possible that you get unenrolled due to an extended absence (usually 1 year or longer), in which case you need to re-enter the enrolment key to get access to your course again.

To obtain your enrolment key again, you need to fill out the same application form for the course as you did when first enrolling. In the application form, you should specify that you have lost your enrolment key. The enrolment key will then be sent in an email to you.