Server Chat example

Hello,
I have been trying to follow the simple chat server from the "An App From Scratch" example.
I am using Visual Studio 2015, with .Net 4.6, 4.5.1 and 4.5.
I am currently having the problem where the OnEvent(EventData eventData) method in my ChatClient.cs does not seem to get called whenever I type out and send a message. Therefore, I do not see any sent messages on the clients.

Any help appreciated.
Thank you very much and best regards.