Cannot install apps anymore or launch the Adobe Creative Cloud Client

Hey,

since today I cannot neither access the list of my installed apps on my Mac, nor install or deinstall new ones. (I don't even see the list of applications)

Neither the web links, nor a new download of the application manager works.

I just get a windows which says:

Download Error

Error 403 Please contact support etc.

No firewalls or settings are inhibiting the network traffic. Everything worked yesterday.