I would love an answer to this as well!

KA is a constant work in progress.  Unfortunately, that means that not all courses can be assigned to the students by the teacher.  Progress can't be seen on courses that are being Beta'd or are not considered complete.  This is the case for the Algebra Basics course, as far as I can tell.

You could submit a support ticket https://support.khanacademy.org/hc/en-us/requests/new or check in Technical Issues and Workarounds https://support.khanacademy.org/hc/en-us/community/topics/200838407