When trying to update orders, is your eBay store receiving a message that reads, "An error occurred attempting to update orders: Auth token has expired"?
If so, you may need to reconfigure your store in ShipStation.
eBay requires that you reconfigure the store once every year when using third-party shipping solutions such as ShipStation.
Read How do I reconfigure my store settings in ShipStation? to learn how to reconfigure your store.