Authorization Question

I am taking a course on SAP Monday December 15th.

I authorized my work computer to start reading, and now can't authorize my laptop at home to download this document.

Getting the "You can only authorize this computer with an Adobe ID that hasn't been previously used to authorize any other computer or mobile devices.  Please try again."

I will be using my home set up for the class.

Any ideas on how I can get this to work on my home set up? 

Please advise.