Once an Adobe DRM book is accessed, the book is locked to the Adobe account/ID in use at the time.
If you want to read it on other devices, you must make sure they are registered with that original ID.
If you change machines you must use the old ID, not create a new one.
If you change email address, you should change the email address associated with the old account/ID; again not create a new one.
Give more details as to your situation, as there are different steps depending on lots of factors: