curl --request POST \
  --url https://www.dench.com/api/v1/crm/transactions/{txnId}/operations \
  --header 'Authorization: Bearer <token>' \
  --header 'Content-Type: application/json' \
  --data '{
  "op": {}
}'

{
  "error": {
    "message": "<string>",
    "type": "<string>",
    "code": "<string>",
    "details": "<unknown>"
  }
}