It can be for different reasons:

1. Check that all your courses and the editions of your courses are active so that they appear in your catalog. In the list that you will find in the "Courses" section of your backoffice you will be able to check if your courses are active or not, and you will be able to edit it if necessary.

2. Check that the start date of a course has not passed. Courses with a start date disappear from the catalog once it has passed, to prevent users from continuing to enroll. If you want that course to always be accessible to users, we recommend that you remove the start date

3. Check that the topics and sub-topics of the course are active. When we deactivate themes from our platform, we must remember that the courses associated with them will not be visible in the catalog. Review the course and change the theme for an active one.

4. Check that the teacher user is active. You can do it from Settings> Users.