Etsy has entered into an exclusive agreement with Shippo and Shipstation, designating them as the only approved fulfilment integrations. As a result, Shopify Marketplace Connect does not have access to order data for new merchant connections, making it impossible for Etsy orders to be sent to Shopify.
Please note that existing connections are not affected by this change.
This is the general release from Etsy
For more information, please see this help article:
How to Use a Third-Party Provider to Ship Your Order