Make sure your course is activated from your Blackboard account.
All course sites are created unavailable by default at the beginning of each
semester. Until a course is made available by the instructor, it cannot be viewed by
students or visitors. Courses that have not yet been made available on the system
will have the (not currently available) label appear next to the course title in the
My Courses module.
If the class has been activated and is still not accessible, please check that the students in question are properly registered for your class and section.