Enter credentials from the client's Partners app. OAuth will run with their Client ID and secret — not the server env credentials.The client's Partners app must whitelist this callback URL: https://connect.skladon.com/custom-app/callbackread_assigned_fulfillment_orderswrite_assigned_fulfillment_ordersread_fulfillmentswrite_fulfillmentswrite_inventoryread_inventoryread_locationsread_merchant_managed_fulfillment_orderswrite_merchant_managed_fulfillment_ordersread_ordersread_productswrite_third_party_fulfillment_ordersread_third_party_fulfillment_ordersread_shippingread_order_edits