ShipStation requires the API keys to be rotated periodically. You will receive a notification from ShipStation with a reminder of the expiration date for the current API keys. Details from ShipStation can be found here: ShipStation API
Create the new keys in your ShipStation account before adding them to the ShipStation settings in Pio.
Update API keys in Pio
Navigate to Pio Admin > System > Software integrations > ShipStation > Account. Add the new keys to the API key and Secret key input fields:
Select the green 'Update API keys' button to confirm: