X-DreamFactory-Api-Key is not allowed by Access-Control-Allow-Headers in preflight response

Hi
I'm currently using bitnami dreamfactory 2.3.0-4. I have setup CORS setting as below

  Origin required 
   *  
  Paths 
   *
  Headers 
   *
  Max Age 
   0
  All methods selected

I created an app in DSP instance and a API key is generated.

Now when I am trying to register a user using http://mydspinstance.com:8080/api/v2/user/register?login=false with X-DreamFactory-Api-Key header set to API key created by dsp, I am getting the below error:

XMLHttpRequest cannot load http://mydspinstance.com:8080/api/v2/user/register?login=false

Request header field X-DreamFactory-Api-Key is not allowed by Access-Control-Allow-Headers 
in preflight response.

The webserver used is nginx if that matters. I am hosting this dsp instance on my VPS via bitnami dreamfactory installer.

BUT when I tested with Advanced REST Client the request completed successfully creating the user.
I think that is because Advanced REST Client make requests on sockets by default, instead on XHR

Can someone provide any clues?? Does it has something to do with interfacing between dreamfactory and postgresql ?

Here my dreamfactory and postgresql logs(I am using postgresql as the default system dbms for dreamfactory):
dreamfactory.log
postgresql.log