When activating the eBook, a message appeared stating that The maximum number of activation has reached?
The ebook, like any printed book, is ONLY one copy. It will only work on ONE computer, that is the one you first used to activate the ebook on. The message means that your ebook is active and running on another computer. If you had activated the ebook on another computer by mistake, you have to deactivate it from that computer first. Then you can activate it on the computer you are going to study. Follow the same activation process for deactivating the ebook on the wrong computer.