Error "E_AUTH_BAD_DEVICE_KEY" –– all forums and knowledge base instructions fail

Here's the most recent article I found; yet, ADE continues to generate the same error. I can't finish authorizing ADE.

https://helpx.adobe.com/digital-editions/kb/error-e_auth_bad_device_key.html

Some history, I've had older versions. Recently, ebooks began claiming auth failed. I followed several articles having eliminated the activation.dat file, ensured date/time correct, modified settings on Keychain access... all to no avail.

Mac OS X 10.13, ADE 4.5.11.187245