WooCommerce Webhook deliver null

I have set up the Webhooks in WooCommerce for order.created. It triggered because I have seen the data in the log. Also I have received the notification from Woocommerce when an order placed and it is also shown in the Webhook logs. But I only receive the null not a json data. I got nothing but only a notify. I need to obtain the “id”, “order_number”, “order_key”…etc in the json in the log. How to get it from the post action? And what is the key of this post action?

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