How to resolve error when using API: The value of the attribute DisputeReason isn't valid

Encountering errors when raising API for receivables dispute, The value of the attribute DisputeReason isn't valid

Code used is as follows

{
  "CustomerTransactionId": 300000085078540,
  "DisputeAmount": 130046508.00,
  "DisputeReason": "RIS US",
  "DisputeSection": "Total",
  "receivablesDisputeLines": [
  {
  "LineDisputeAmount": 130046508.00,
  "CustomerTransactionLineId":300000085078541
  }
  ]
}

Looking into the credit_memo_reason in receivables look up, the value is valid