eBay requires a reconfiguration after certain settings have been changed or a certain amount of time has passed. eBay specifically requires a reconfiguration once a year.
Multiple eBay Stores
If you're reconfiguring multiple eBay stores in ShipStation, we recommend you log out of any active eBay sessions before reconnecting the accounts.
Receiving a 404 Error? You may need to migrate to the new eBay integration.
The basic steps to reconfigure your eBay store are:
Edit your Marketplace Connection in ShipStation's store Settings.
Re-enter your connection details for the store.
Authorize the connection on your eBay account
Refresh the store on the Orders grid.
For detailed steps to reconfigure your store, see below: