Cannot activate my computer with my Adobe ID after having activated my ebook reader

I cannot activate my computer with my Adobe ID after having activated my ebook reader with the same ID. I get the error message: "You cannot authorize this computer with an Adobe ID that was previously used to authorize another compuer or moblie device". Shouldn't it be possible to use the same ID on more than just one device? I would like to read the same book on my ebook reader and on my computer.