Configure microsoft teams incoming webhook json payload

I am trying to set up an incoming webhook to a Microsoft teams channel using the incoming webhook connector.The payload that I am trying to send from my platform looks like this and is form CleverTap (which is failing so I'm trying to debug it using postman). but I am getting the error Summary or Text is required.

{"profiles": [    {"email": "jack@gmail.com","identity": "foo","objectId": "-g55b74fb1030740e4a4931910a8abb862","profileData": {"Last Score": 308,"High Score": 308,"Replayed": true      },"name": "Jack"    }  ]}

1. What am I doing wrong?
2. will I need to change the JSON payload according to the adaptive card syntax for teams to accept the incoming webhook? If so, where can I add my custom payload in the adaptive card JSON body?
3. are there other authentication factors at the webhook endpoint (do I have to whitelist the ip address from where the POST message is being sent from)?