I just installed a Whonix Gateway VM on VirtualBox and setup my Debian VM to use the Whonix Gateway to connect to the internet.  

So far all good. When I visit check.torproject.org it tells me I´m using Tor...  

But somehow I am not able to access tor hidden services. For instance I am not able to visit the hidden wiki page through the web browser on my Debian VM.  

My thought was as my connections are going through the Tor network anyways, it should be obvious I am able to connect to the hidden services...  

Why is it not working (curl is saying 'Empty reply from server') and what do I have to do to make it work?

Thank You. :)