Hard to know. Maybe you have the wrong password. Maybe you don't have a valid copy. Maybe you need to de-activate MATLAB on some old machine, where you thought it was already deactivated. (That last did happen to me recently.)
Either you need to offer much more informmation about what does happen when you try and what fails, or you need to contact customer support directly. Answers is not customer support in any way. We have no access to any information to know what might be the issue, and we cannot fix any problem that may be the case for you.
