Error in Adobe Digital Editions
Downloaded ADE 4.5.7 got this error when trying to open the how-to book
Client certificate used with Digital Editions is invalid. You will not be able to use all the features available in this application!
No clue why. Please fix.
I am assuming your concerns have been resolved. Let us know otherwise.
I would request you to uninstall the current ADE version from your machine and download/install the updated ADE installer from the following URL and see if that resolves the issue-
Let me know if you face any issue.