Hello, I received the Giga connect box today and I am facing the same problem during installation.
after looking at the socket online I think it can be a wrong socket, not good for internet connection. The socket productor and model is: Triax GAD 269. A photo is attached. 
We have no other coaxial sockets in the apartment. We have another kind of socket, a photo of it is also attached.
On top of that we also have the fiber outlet.
Is the socket we have good enough or do we need something else?
My customer number is 7255832
Greetings,
E