Adobe Digital Editions authorization problem

I bought an e-book from google play and I  downloaded the epub version of it. I used  the Adobe Digital Editions via of which, I transferred it at my e-book reader. I put as password and username the corresponding credentials of my ID Adobe acount, but authrization failed. I  put instead of my password the serial number that is shown at product info at ADE and was shown a different message but again the authorization failed. Does he know anyone what can be the problem about that?