The astrophysics course started with a welcome message to the students, inviting use to watch a video. Unfortunately my home bandwidth is limited, so I clicked on the link in the email which took me to the course website to read the introduction. However, under the headings "Course Updates & News" and "Course Handouts" I couldn't find any content. It seemed odd that neither the welcome video, nor a text alternative (as required under Australian anti-discrimination law) was provided.
So I then went to the "courseware" page, which asked me for a user-id and password. It is some months since I signed up and could not remember the password, so I requested this be reset. So far the reset email has not arrived. So the only Great Unsolved Mystery so far with this course is "where is the content?". ;-)