If your students are reporting that they cannot see your course, it may still be in a hidden state. You must change the "Course visibility" setting (under the course settings) from "hide" to "show."
1) From within your course, click on "Edit settings," on the gear menu.
2) On the Edit course settings page, under the General category, look for and change the "Course Visibility" setting.
3) Save your changes.
More Information
This Course visibility setting of a course determines whether it appears in the list of courses or not. If a course is "hidden" it appears only to users who are enrolled as Teachers in that course, as well as Moodle administrators. Students or other "Teachers" will not see the course listed anywhere.