I can not authorise my device or computer

I hope you can help.....?

When I select Adobe ID as the ebook vendor and enter my Adobe ID and password, the error message which comes up says that username or password is incorrect so I cannot authorise any device or computer inorder to read my ebooks. I can log onto Creative Cloud and the Adobe Apps on my iPhone or iPad without any problem. Why does Adobe Digital Editions not work for me?

Thanks for your help