I'm using the endpoint https://{accountName}.{environment}.com.br/api/fulfillment/pvt/orders for create orders, passing an URL in the marketplaceServicesEndpoint field on request body for receive the order status changes notifications.
I'm using pages that give me a URL that collects requests sent by VTEX (For example - https://webhook.site/), but the request never arrives.
I'm having the same problem on my site.
I suspect that the cause of this is that VTEX is not sending the header Host.