After you click Export to Root Planner the page lists what happened:

• Export Results — one row per successful step, e.g. "Customer Created - #123", "Customer Update - #123" or "Order Created - #<tracking code>", with a reference (User #, Checkout # or Pickup #) and the order numbers included.
• Export Errors — one row per failed step with the reason returned, e.g. "Customer Create - …", "Order - Invalid Hub on Kitchen Location #2" or "Order - Invalid Rootplanner CustomerId".

Orders listed under an error keep no tracking code, so they will be exported again the next time you run the export once the cause is fixed.