If you have an Enrollee who is not showing up on the Instructor portal to be checked in, it may mean that the Enrollee was not checked out. To see if this is the case, follow these steps:
In the Admin portal, go to the Classes page
Click on the Enrollee's timeline under the Class they are enrolled in
If any check-ins DO NOT have a check-out, for EACH listed, click on the edit pencil and then click "Create Check Out Activity"