When processing orders, you might come across the "Platform not authorized" error.
This error is shown when the Canada Post account setup was completed but with issues in the internal process.
1- If you have set the Billing Account on Clients, remove it/them
2- Notify techShip support of the action so a complete removal by the Support team is performed
3- Upon notification from the techShip support team, begin the Canada Post account set up process as described here: Registering Canada Post Account
Once completed, you should be able to set the Billing Account on Clients again and operate successfully.