Help! Can't uninstall Cubase 10 on PC (Win 10)

Ok, a new error now happened!

I have Cubase Pro 10.0.40 Build 284 - Build on August 22 2019

installed, and now downloaded the installer for 10.0.60 (the only one available via the link you provided me).

Now when I tried to install it, I get this error message:

Error Code: 1612
Installation of Cubase 10.0.60 Update failed.
Die Installationsquelle für dieses Produkt ist nicht verfügbar. Stellen Sie sicher, dass die Quelle vorhanden ist und Sie Zugriff darauf haben.

I am a bit puzzled by this to say the least.
Would you have a suggestion?

PS: I just found this, maybe this will work?