대납 처리시 에러가 발생하는데 "txError": "0x9" 는 어떨때 발생을 하나요?

NFT 발행시 대납을 구현 중입니다.
아래와 같이 코드 진행중인데 sendSignedTransaction시 에러가 나오는데
무엇이 문제 인지 모르겠습니다.

const sender = this.getWallet();

//대납계정

const feePayerAddress = '0xcb7a63b37cc7600ff6053017f3f26de1e99554e8';
const feePayerKey = '471599634d14e302388d2c516b6299e86f8c4022f9f4a8a2d966a3e9076ba4dc';
const feePayerAccount = cav.klay.accounts.createWithAccountKey(feePayerAddress, feePayerKey);
cav.klay.accounts.wallet.add(feePayerAccount);

const tx = {
  type: 'FEE_DELEGATED_SMART_CONTRACT_EXECUTION',
  from: sender.address,
  to: DEPLOYED_ADDRESS,
  data: yttContract.methods
        .mintYTT(
          videoId,
          author,
          dateCreated,
          "https://ipfs.infura.io/ipfs/" + hash
        )
        .encodeABI(),
  
  gas: '500000',
  value: cav.utils.toPeb(1, 'KLAY'),
  
}
const sender_signed = await cav.klay.accounts.signTransaction(tx)


console.log(new Date().toLocaleString('en-US', { timeZone: 'Asia/Seoul' }), `signTransaction TX : ${JSON.stringify(sender_signed)}\n`)

const tx_for_fee_payer = Object.assign({ signatures: sender_signed.signatures }, tx)

const fee_payer_signed = await cav.klay.accounts.feePayerSignTransaction(tx_for_fee_payer, feePayerAccount.address)
console.log(new Date().toLocaleString('en-US', { timeZone: 'Asia/Seoul' }), `feePayerSignTransaction: ${JSON.stringify(fee_payer_signed)}\n`)

tx.signatures = sender_signed.signatures;
tx.feePayer = feePayerAccount.address;
tx.feePayerSignatures = fee_payer_signed.feePayerSignatures;

const send_tx_receipt = await cav.klay.sendSignedTransaction(fee_payer_signed);

console.log(new Date().toLocaleString('en-US', { timeZone: 'Asia/Seoul' }), `sendSignedTransaction: ${JSON.stringify(send_tx_receipt)}\n`)

},

===========================================================================
6/23/2022, 4:08:48 PM signTransaction TX : {“messageHash”:“0x1350e96b35851ade076aeb5b92f479f188d134fa8606303110a8758889275ac8”,“v”:“0x07f5”,“r”:“0xb6cd34d3b37dc0017b8d0c08323c939e0b9bf097d46d7ca715e5877c2c97d9f0”,“s”:“0x3bf00a1ca3f59619d9582668072b828b60ea3f12871ed429ef69a1588255c32b”,“rawTransaction”:“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”,“txHash”:“0x783cf3862747c20d566c1a234f3ebd89e270bb71b043d0c4899ca35787ecbd9e”,“senderTxHash”:“0x2cf92a09788285cbfd8a817e9ab316a5795273c7b16c12640900daf74de2cd3e”,“signatures”:[[“0x07f5”,“0xb6cd34d3b37dc0017b8d0c08323c939e0b9bf097d46d7ca715e5877c2c97d9f0”,“0x3bf00a1ca3f59619d9582668072b828b60ea3f12871ed429ef69a1588255c32b”]]}

index.js:304 6/23/2022, 4:08:48 PM feePayerSignTransaction: {“messageHash”:“0x899792e953da3da61e80448c4a75ca2f9770401f30df7b68b272797f62cdcfef”,“v”:“0x07f6”,“r”:“0xf10a73347e01bffb4817d25ffee99b54e7a12d5ced781365a3931f060f6ffaa4”,“s”:“0x7816c4748e52e5e06b07012e8359e2618c5097c29c92f38e79c606b528f5ae89”,“rawTransaction”:“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”,“txHash”:“0x03b2a8b51ce612c4809f4efb9dbbf8220c1b99d5050e0eb58c1a4e47924bafeb”,“senderTxHash”:“0x2cf92a09788285cbfd8a817e9ab316a5795273c7b16c12640900daf74de2cd3e”,“feePayerSignatures”:[[“0x07f6”,“0xf10a73347e01bffb4817d25ffee99b54e7a12d5ced781365a3931f060f6ffaa4”,“0x7816c4748e52e5e06b07012e8359e2618c5097c29c92f38e79c606b528f5ae89”]]}

index.js:692 Uncaught (in promise) Error: evm: execution reverted
{
“blockHash”: “0x0f409ee989508ae5457a90686372da56b7cfdab6aea1a4d62499998ebee39f8c”,
“blockNumber”: 94393521,
“contractAddress”: null,
“feePayer”: “0xcb7a63b37cc7600ff6053017f3f26de1e99554e8”,
“feePayerSignatures”: [
{
“V”: “0x7f6”,
“R”: “0xf10a73347e01bffb4817d25ffee99b54e7a12d5ced781365a3931f060f6ffaa4”,
“S”: “0x7816c4748e52e5e06b07012e8359e2618c5097c29c92f38e79c606b528f5ae89”
}
],
“from”: “0x4210a426a7bfb4b5a2feb3c0a1803f2642c670f0”,
“gas”: “0x7a120”,
“gasPrice”: “0x3a35294400”,
“gasUsed”: 76245,
“input”: “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”,
“logs”: ,
“logsBloom”: “0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000”,
“nonce”: “0x2d”,
“senderTxHash”: “0x2cf92a09788285cbfd8a817e9ab316a5795273c7b16c12640900daf74de2cd3e”,
“signatures”: [
{
“V”: “0x7f5”,
“R”: “0xb6cd34d3b37dc0017b8d0c08323c939e0b9bf097d46d7ca715e5877c2c97d9f0”,
“S”: “0x3bf00a1ca3f59619d9582668072b828b60ea3f12871ed429ef69a1588255c32b”
}
],
“status”: false,
“to”: “0x55f976d6bc273a2ade249f62732a601b6023445e”,
“transactionHash”: “0x03b2a8b51ce612c4809f4efb9dbbf8220c1b99d5050e0eb58c1a4e47924bafeb”,
“transactionIndex”: 18,
“txError”: “0x9”,
“type”: “TxTypeFeeDelegatedSmartContractExecution”,
“typeInt”: 49,
“value”: “0xde0b6b3a7640000”
}
at checkForNormalTx (index.js:692:11)
at eval (index.js:573:11)

가스부족이 원인일 가능성이 있습니다.
50만보다 크게 세팅해서 충분히 큰 값으로 두고 다시 한번 시도해 보시겠어요?

baobab에서 테스트하는거라 KLAY도 충분히 있고,
가스비도 10,000,000까지 설정해서 시도 해봐도 같은 에러가 나오네요.
대납관련하여 참고할만한 샘플이 있을까요?