oData with C# .Net

Hello,

I try to create my first oData Application with .Net.

I read the Articel from Maria Trinidad MARTINEZ GEA

How to consume Service Layer oData services from .NET via WCF

And set the setting like in the Articel, but I always get the Error 400.

I'm not sure what I have to do with this sentence:

"Note: In order to be able to get the metadata you need first to open a session wiht Service Layer, for example via PostMan or any other tool."

Maybe this is the reason for the error.

Regards,

Thomas