At the moment, CatLight cannot connect to teamcity if only NTLM is used.
GitExtensions is having the same Issue currently.
To workaround this issue it's possible to get an authentication cookie when ntlmlogin.html page is browsed.
This authentication cookie can than be passed for further rest calls.
a powsershell sample can be found in the answer from mclayton on http://stackoverflow.com/questions/11020066/log-onto-teamcity-server-using-rest-api-without-passing-credentials-in-the-url