Scope

This issue can occur when ShipStation throws a 404 error while creating/updating an order (SSOrderAPI.java:619)

Solution

ShipStation throws this error in 2 scenarios 

1. Order is deleted in ship station or split or merged with other orders.
2. Order is moved to a different manual store in ShipStation.

If multiple orders are mapped to the same order in Shipstation i.e. all those orders have been merged in ShipStation. So when Chargebee tries to find the record during sync it throws a 404 error.

If shipped, then you can click that Ignore button on the ShipStation Sync window to ignore these records.