DRM not authorized error when trying to open ebook on kobo, what do I do?

I've authorised my computer and my kobo device with my adobe account and then moved the file into my kobo in the left sidebar but it doesn't open on my kobo. It says "oops! this document cannot be opened.  This document is protected by Adobe DRM and is not currently authorized for use with your Adobe ID. Please sign in and try again."  What do I do?