That sounds like an issue with the Creative Cloud app itself. I suggest reinstalling Creative Cloud. Then reinstall Photoshop. If that doesn’t fix it then I think you will need to contact Adobe so they can fix Creative Cloud. Just tell them it’s not able to install CCX files. They should be able to help you with it.
Fixing Creative cloud is beyond what I know how to do, other than reinstalling it (which usually fixes it).
Anyway, let me know if reinstalling CC fixes it. Or if Adobe has to fix it, then I’d like to know what they had to do to fix it.