Alchemy C# Websocket handshake

Question

I use Alchemy in C# for a websocket server. Both Firefox and chrome can connect to the server. But NodeWekit gives a error (it is the same page).

In nodewebkit I get "WebSocket connection to 'ws://localhost:7980/' failed: Connection closed before receiving a handshake response"

I have no clue what to do now. Does someone has a idea? of a better C# server lib?

Thanks already!