Create subscription - Walmart API Notification 415 Error

I am trying to make the request API /v3/webhooks/subscriptions from Walmart but it response for me 415 Unsupported Media Type

I have assign Accept and Content-Type is application/json in headers What should I go next to solve this?

curl --location 'https://marketplace.walmartapis.com/v3/webhooks/subscriptions' \
--header 'WM_SEC.ACCESS_TOKEN;' \
--header 'WM_QOS.CORRELATION_ID: 4abf82fc-222c-4def-a498-7eadfc36f825' \
--header 'WM_SVC.NAME: Walmart Marketplace' \
--header 'Authorization;' \
--header 'Accept: application/json' \
--header 'ChannelType;' \
--data '{
    "events": [
        {
            "eventType": "PO_CREATED",
            "partnerId": "",
            "eventVersion": "V1",
            "resourceName": "ORDER",
            "eventUrl": "",
            "status": "ACTIVE"
        }
    ]
}'

Here is the cURL I make. Please don't pass Content-Type in Header.If you try to call by Postman please try to remove the default value Content-Type is make by Postman