- Could not edit inventory - Error Creating Inventory Missing required field - fulfillmentlagtime
As the error outlined fulfillmentLagTime (located in the Inventory Fields of the Walmart Custom Fields Mapping) is a required field and you would need either to map an existing field or to create a new custom field, if there isn't any dedicated field to contain those values and then map it so they could be pushed to Walmart.
- According to Walmart "Fulfillment Lag Time determines the number of days it takes the Seller to prepare an order for shipment. Whole numbers like 0, 1 and 2 are acceptable values for that field. For additional information regarding Fulfillment Lag Time and how it affects Expected Ship Date, see Marketplace Shipping Standards."
You can take a look as a reference at this Walmart material and you would be able to see some more information about the Fulfillment Lag Time attribute and also please see the screenshot below: