Can't get ADE to work

My public library supports CloudLibrary, which allows me to download books. The books open without any difficulty on my PC. I am also able to transfer them to ADE, and from there to my Kobo.

Here's the problem: the books will not open in ADE (the app just sits there) and when I try to open them on the Kobo, I get the "no permission to copy" message. I have tried deauthorizing and reauthorizing but nothing works. I have uninstalled and reinstalled. No luck there either. Is the app just buggy or is there a fix? I am running Windows 11. Thanks in advance for any assistance!