curl --request GET \
  --url https://api.modulate.aurorapayments.net/api/v2/partner/merchants/{merchant_id}/gateway-transactions/{gateway_txn_id} \
  --header 'X-Partner-API-Key: <api-key>'

{
  "detail": [
    {
      "loc": [
        "<string>"
      ],
      "msg": "<string>",
      "type": "<string>",
      "input": "<unknown>",
      "ctx": {}
    }
  ]
}