DRM Error on Kobo

I downloaded a eBook from my local library and transferred to my Kobo through ADE but it won't open on the Kobo. I get an error message saying the document is protected by DRM.

I've authorized ADE on my PC, checked that device is authorized, checked that both authorizations are under the same ID, checked that the ID is the same as the email address my library has, deleted and redownloaded the book, uninstalled and reinstalled ADE, returned the book to the library and reborrowed it, but nothing has worked. I get the same error message no matter what I try. Please help!