How do I set up Digital Editions with a new email?????

I changed my Adobe ID after shutting down my website, so had to change the old email which no longer existed to a new one. That worked for all my applications except Digital Editions which still seems to be connected to my old email and hence gives me the following error message when I try and add new library books:

Error getting License. License Server Communication Problem:
E_AUTH_BAD_DEVICE_KEY_OR_PKCS12

How do I update my email in Digital Editions? I can't de-authorise from the old one as when I try and enter the old email and pw it just says 'Unable to Erase Authorization'. Maybe because that email no longer exists???

I've tried uninstalling and reinstalling and nothing works. How do I fix this?