yes I am using the default session (I omitted the session assignment in previous post sorry) at the moment.
var aI = location.AppWithId(qlikSenseAppId, noVersionCheck: true); var defaultSession = Session.WithApp(aI, SessionType.Default);
I tried the custom session too (adding the parameter '&identity=MyCustomSession' in the 'Single' url) but it doesen't seem to share the same engine session:
var customAppSession = Session.WithApp(aI, "MyCustomSession");
I see you are adding network credentials to your AsNtlmUserViaProxy call. Are you sure you end up with the same user as the one you get when you go through a browser?
Other than that it looks correct to me. I seem to remember that there was an issue with the session matching in some older version of Qlik Sense though, so just to be sure: which version are you running?
Anyway, for reference, here is the exact code I used for connecting to the client session during my talk at Qonnections this year: https://github.com/kolsrud/qonnections2018_demo/blob/master/QonnectionsDemo/Program.cs
That program connects to a desktop and the selection performed at the last line is reflected in the Qlik Sense client.