Authenticating Cloud Orchestrator using HTTP Request Activity

I am able to invoke Cloud Orchestrator APi using postman

![image|690x367](upload://26hVRrl0pzzUuAqhlrJWRoqHltD.png) 

When I am trying to invoke Cloud Orchestrator API using HTTPRequest activity i am getting invalid json error.

I have specified

under OAuth1
CustomerKey
CustomerSecret

under Options i have specified
Json against Body

If someone have used this approach please let me know what is wrong here.

I am also facing the same issue, if you have found any solution can you please help me here?

i am receiving the error 400- Invalid JSON