Getting issue in connecting with Dot net Core Web API from Angular 1 CORS issue

We have tried several settings, previously we were getting "'Access-Control-Allow-Origin'" issue and we fixed it with below settings.

XMLHttpRequest cannot load http://ift.tt/2vOyIFE. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'localhost:9000' is therefore not allowed access.

Did settings in web config after publishing the code:

  <httpProtocol>
        <customHeaders>
          <add name="Access-Control-Allow-Origin" value="*" />
        </customHeaders>
   </httpProtocol>

After succesfully resolve above issue we are getting different issue:

After this error changes to this: XMLHttpRequest cannot load "http://ift.tt/2gOsSxp". Response for preflight has invalid HTTP status code 400

Please guide me.

Thanks, Ritesh