Library ebooks asking for Adobe ID and Password?

I recently purchased a new Nook. When I try to open my library downloads, I am prompted to enter my Adobe ID and password...which doesn’t work. I never had to follow this step in the past. I have the latest version of Adobe and I have authorized my computer and device. My passwords are synced with Overdrive. I am completely stumped. So is my librarian. Any thoughts or help?