All students receive temporary access to eBooks in Blackboard for the first 21 days of class. If the student has not initiated a login via Blackboard after this period, it is possible they were not provisioned a full license. Try logging in through Blackboard, and then resuming access outside of Blackboard. 

Additionally, when accessing some access codes/courseware, the publisher may require you to register your code. If the student skips this step and continues without registration, it may prompt their system to give 14-day temporary access to the student instead of the purchased materials through Course Ready.