Failed to open the ebook from AICPA

I have just purchased an ebook from the AICPA and downloaded the Adobe Digital Edition to open the book. However, when I use the same credential as the AICPA to login the Adobe Digital Editions, it told me that

Incorrect login ID or password for the selected eBook vendor. Please try again

But if I use the other Adobe ID or not use the Adobe ID, it would tell me that :

Error getting License. License Server Communication Problem:

E_LIC_ALREADY_FULFILLED_BY_ANOTHER_USER

Any idea how to solve this issue?

Thanks a lot!

Saini