So da sich leider keiner gemeldet hat habe ich ewig alles versucht und nun endlich die Lösung gefunden:
you are comfortable in the registry: open run: regedit and Try this:
HKEY_LOCAL_MACHINE\Software\Policies\Microsoft\Win dows\CurrentVersion\Internet Settings
On the right side, you'll find a file named:
"ProxySettingsPerUse" or "Default"
Click it and change its value to "1" (obviously without the " "). Then you accept.
From: Gabriel Lobo on

A few responses said it worked for them.
It worked for me too