Getting 400 bad request: Authentication Message on Apple Business Chat

{
    "type": "interactive",
    "id": "f57d6be1-5329-43a4-b4e8-92babdda59o2",
    "v": 1,
    "sourceId": "urn:mbid:AQAAY4s8T/DWO0nUZxiqixyTXe3Q TRUNCATED",
    "destinationId": "6f7f7f2d-d4a6-46d5-TRUNCATED",
    "interactiveData": {
        "bid": "com.apple.messages.MSMessageExtensionBalloonPlugin:0000000000:com.apple.icloud.apps.messages.business.extension",
        "data": {
            "version": "1.0",
            "requestIdentifier": "7d8004b6-8827-4f32-b3f0-3a5fb36b203a",
            "authenticate": {
                "oauth2": {
                    "responseType": "code",
                    "scope": [
                        "email",
                        "profile"
                    ],
                    "state": "xyz",
                    "clientIdentifier": "abc",
                    "responseEncryptionKey": "MFYwEAYHKoZIzj0CJByFOYSigUnZ6nj",
                    "clientSecret": "client_secret"
                }
            },
            "images": [
            ]
        },
        "receivedMessage": {
            "title": "Sign In to Business Chat Sandbox"
        },
        "replyMessage": {
            "title": "Authentication Failed"
        }
    }
}

This is the sample payload I'm sending to the POST authenticate endpoint and I keep on getting 400 Bad Request. The payload seems correct as per the documentation. I'm also listing down the headers I'm using below:

Content-Type application/json
Destination-Id 6f7f7f2d-d4a6-46d5-TRUNCATED
Source-Id": urn:mbid:AQAAY4s8T/DWO0nUZxiqixyTXe3Q-TRUNCATED
id f57d6be1-5329-43a4-b4e8-92babdda59o2
version 1.0
Authorization Bearer eyazm...

The responseEncryptionKey is secp381r public key

Replies

The group is created to discuss cases related to apple review, developer accounts, apple support etc. Please share you experience with other members! Join on Telegram to the applesubmission.