Safari(iOS9) and Windows Authentication (NTLM) issue

We have a Web API with windows authentication on IIS 7.5 and windows server 2008 R2. This service is working fine on iOS8.4 but the problem started when users are trying to access it from iOS9.1. Chrome on both the iOS version is working fine but Safari is not.

We are accessing this service through a simple CORS request with default content-type(no preflight request). Also,

Access-Control-Allow-Credentials

Access-Control-Allow-Origin are set properly. I have also tried with other headers but no luck. Any help is much appreciated.