what happens if you disable sync'g fonts and files?
But I click on asset right because I want to activate a new font, actually.
I've seen some other reports of this issue related to the Creative Cloud app not being installed correctly. I'd try uninstalling/reinstalling it as described here: Uninstall the Adobe Creative Cloud desktop application
If the issue persists after doing so, I'd suggest contacting and working with our support directly
Hope that helps,