HE Student Knowledge Base URL: http://cmg.screenstepslive.com/s/MacmillanMedia_StudentHelp/m/52448/l/609348
Make sure that you are inputting the PIN correctly. The PIN is case-sensitive, so all capital/lowercase letters must be entered exactly.
Do not use the same PIN as a previous semester. Each PIN is good for one semester only.
If your PIN is still invalid, please contact technical support and we will investigate the issue.