curl --request GET \
  --url https://api.hubapi.com/conversations/v3/conversations/threads/{threadId}/messages \
  --header 'Authorization: Bearer <token>'

{
  "paging": {
    "next": {
      "link": "",
      "after": ""
    }
  },
  "results": [
    {
      "type": "MESSAGE",
      "id": "<string>",
      "conversationsThreadId": "<string>",
      "createdAt": "2023-11-07T05:31:56Z",
      "updatedAt": "2023-11-07T05:31:56Z",
      "createdBy": "<string>",
      "client": {
        "clientType": "HUBSPOT",
        "integrationAppId": 123
      },
      "senders": [
        {
          "actorId": "<string>",
          "name": "<string>",
          "senderField": "<string>",
          "deliveryIdentifier": {
            "type": "<any>",
            "value": "<any>"
          }
        }
      ],
      "recipients": [
        {
          "actorId": "<string>",
          "name": "<string>",
          "deliveryIdentifier": {
            "type": "<any>",
            "value": "<any>"
          },
          "recipientField": "<string>"
        }
      ],
      "archived": true,
      "text": "<string>",
      "richText": "<string>",
      "attachments": [
        {
          "fileUsageType": "<string>",
          "name": "<string>",
          "type": "FILE",
          "url": "<string>",
          "fileId": "<string>"
        }
      ],
      "subject": "<string>",
      "truncationStatus": "NOT_TRUNCATED",
      "inReplyToId": "<string>",
      "status": {
        "statusType": "SENT",
        "failureDetails": {
          "errorMessageTokens": {},
          "errorMessage": "<string>"
        }
      },
      "direction": "INCOMING",
      "channelId": "<string>",
      "channelAccountId": "<string>"
    }
  ]
}