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 "Settings" menu option at the top of the page.
2) On the "Edit course settings" page, under the General category, make sure the "Course Visibility" setting is set to "Visible".
3) Save your changes.
More Information:
The "Course Visibility" setting 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 (and Moodle administrators). Students will not see the course listed anywhere.