Issue transferring ebooks to Kobo Aura

Since updating to ADE 4.0, I have been unable to transfer books borrowed from my local library to my Kobo Aura (my library uses the Overdrive platform). Every time I try to transfer a book and try to open it, I get the error message "Oops! This document couldn’t be opened. This document is protected by Adobe DRM and is not currently authorized for use with your Adobe ID. Please sign-in with the authorized Adobe ID and try again." I have tried deauthorizing then reauthorizing both my computer and the Kobo, resetting the Kobo (not a factory reset yet, just basic), uninstalling and reinstalling ADE (including reverting to versions 2 and 3, both of which result in a different error that prevents the books from being downloaded at all) and have had no success.

I contacted Kobo's customer support and this is what they told me to do (spoiler: it didn't work):

Please follow these steps:

1) Launch Adobe Digital Editions

2) To Deauthorize the Computer hit Ctrl+Shift+D

3) Close Adobe Digitial Editions

To Reauthorize ADE to your computer:

1) Launch Adobe Digital Editions

2) Click on the downward arrow to the right of the Library menu

3) Select “Authorize Computer”. You will see a message stating that your computer has been authorized.

After this delete the complete program from your computer.

Install the program Adobe Digital Edition 2.0

What else can I try? For reference, I am on a Mac, using OS X Yosemite version 10.10.3.

Thank you.