It used to open Creative Cloud and allow me to install locally.
Since a couple of days this doesn't work anymore. I tried every solution advised here and on the adobe pages. Even repaired the Creative Cloud app. The .ccx file is still connected to the correct adobe app (UnifiedPluginInstallerAgent).
Nothing happens when I double click on the .ccx file. Files that installed before don't work anymore either.
It looked like I had no rights (permissions) to access files from within the Creative Cloud app. I made an exception in the firewall and then things worked like they should. In my case, the Windows 11 defender firewall is managed by the Avast! premium antivirus program. Problem solved!