I'm trying to cancel a freight pickup using the FedEx API, but I keep receiving the following error:

{
    "transactionId": "APIF_SV_PUDC_TxIDd7cc20b2-bee1-4131-89eb-a8bf3216057f",
    "errors": [
        {
            "code": "FREIGHT.PICKUPCONFIRMATIONCODE.INVALID",
            "message": "Missing or invalid confirmation number. Please update and try again."
        }
    ]
}

API Endpoint:

Request Payload - Valid Payload

{
  "associatedAccountNumber": {
    "value": "510XXXXX0"
  },
  "pickupConfirmationCode": "20230620COS457822",
  "remarks": "This is my remarks",
  "reason": "This is my reason",
  "contactName": "This is my contactName",
  "scheduledDate": "2025-03-19"
}

What I Have Tried:

Used a valid Pickup Confirmation Code obtained from a previous request. Tested multiple payload variations, including the exact sample payload from FedEx freight documentation. Verified that the API credentials and authentication tokens are correct. Checked if the issue is due to sandbox limitations by testing in the FedEx test environment.

Questions:

Has anyone encountered this error when canceling a freight pickup using the sandbox FedEx API? Are there any additional requirements for the Pickup Confirmation Code that I might be missing? Could this be a sandbox environment limitation, and would switching to a production account resolve it? Any insights or suggestions would be greatly appreciated!