I reloaded Adobe digital editions and now when trying to add a book, it says not authorized by ADE

Authorize computer is greyed out, it says this computer already authorized.

I tried to add the serial number for my Kobo and it says not valid with my

adobe ID

I have added a book to ADE from the public library, I can open it, however

when I try to download to my kobo it says not authorized for use with your

adobe ID.

I have no idea what my adobe ID is!