Adobe Digital Editions 4.5 - Password Change

My Kobo ereader has been working great, when all of a sudden, there is now an error that pops up when I try to open a book. The error says: "this document is protected by Adobe Digital Rights Management (DRM) and is not currently authorized for use with your Adobe ID. Please sign-in with the authorized Adobe ID and try again." I'm not sure why this popped up since I didn't do anything differently. 

I looked at a lot of forums to figure out what to do and it seems like I need to deauthorize my computer while in Adobe Digital Editions by pressing "Command" + "Shift" + "D". However, I am unable to deauthorize because Adobe Digital Editions is associated with an old email address and my password also does not work. 

I changed my Adobe ID password online in hopes that it would automatically apply to Adobe Digital Editions, however it has not. 

Can someone please help me with the following:

1. How do I change my email and password with Adobe Digital Editions?

2. Are there any other suggestions as to how I can read my books again?

Thank you.