It's possible to accidentally setup a WordPress Courses site which automatically redirects to the HTTPS version of the site instead of HTTP. When this happens, resources required by the theme and images in the course may not load correctly.
To fix this issue:
- Login to the Courses site as usual
- In the left hand sidebar, hover over "Dashboard" and click on "My Sites"
- On the "My Sites" page, click the "Manage Sites" link at the top left
- Find for your site in the list of Sites
- Hover over your site, and click "Edit"
- On the "Edit Site" page, click the "Settings" tab
- Make sure that the "Siteurl" and "Home" inputs start with "http://"