ServiceStack/ServiceStack — pull request #858 by dchurchland (2013-11-08 00:37:26+00:00)
Title: throw meaningful message when header does not include a space

I am not sure if this is the best way to achieve this but I wanted a more meaningful error when the IIS Application is using Windows authentication (thus returning the auth header 'Negotiate,NTLM') and the client has sent a user name and password, rather than a Credentials object.