By default ServiceStack’s AuthFeature will only try to redirect you to the default ~/login
path for HTML Content-Type requests. You can override this by setting the redirect path in the AuthFeature to null:
Plugins.Add(new AuthFeature(...) { HtmlRedirect = null });
This will fall back to the standard 401 UnAuthorized
Response that the other Content-Types get.
After globally setting the HtmlRedirect to null, you can add it back on an adhoc basis, e.g:
[Authenticate(HtmlRedirect="~/path/to/redirect/to")]