# kip7Instance.burn 실행시 오류

**URL:** <https://devforum.kaia.io/t/kip7instance-burn/2570>\
**Category:** Caver\
**Created:** [11월 28, 2021, 6:51오전 UTC](https://devforum.kaia.io/t/kip7instance-burn/2570 "2021-11-28T06:51:21Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![GregSeo](https://yyz1.discourse-cdn.com/flex035/user_avatar/devforum.kaia.io/gregseo/32/2138_2.png) [@GregSeo](https://devforum.kaia.io/u/GregSeo)\
**Post date:** [11월 28, 2021, 6:51오전 UTC](https://devforum.kaia.io/t/kip7instance-burn/2570/1 "2021-11-28T06:51:21Z")

</div>

caverjs를 이용하여 테스트 넷에서 발행된 토큰의 소각을 진행하면 오류가 발생하네요.

```auto
const fs = require('fs')
const Caver = require('./node_modules/caver-js/index')
//const caver = new Caver('https://api.baobab.klaytn.net:8651');
const caver = new Caver('https://kaikas.baobab.klaytn.net:8651');

const address = "0x...{Owner wallet address}....bc";
const contractAddress = "0x...{Contract address}..0d";
    
const keystore = fs.readFileSync('./baobab-keystore.json', 'utf8')
const keyring = caver.wallet.keyring.decrypt(keystore, '{password}')
console.log(keyring)
caver.wallet.add(keyring)
    
const kip7Instance = new caver.klay.KIP7(contractAddress);
    
//kip7Instance.name().then(console.log);
//kip7Instance.decimals().then(console.log);
//kip7Instance.totalSupply().then(console.log);
//kip7Instance.balanceOf(address).then(console.log);

kip7Instance.burn(1000, { from: address, gas: 210000, gasPrice: 25000000000 }).then(console.log);

```

이렇게 실행을 하면, name, decimal, totalSupply 모두 출력되는데, kip7Instance.burn 실행시에는  
UnhandledPromiseRejectionWarning: Error: Returned error: unknown account  
에러가 발생합니다.

혹시나 테스트넷이 잘못된건지 해서  
[https://api.baobab.klaytn.net:8651](https://api.baobab.klaytn.net:8651) 랑 [https://kaikas.baobab.klaytn.net:8651](https://kaikas.baobab.klaytn.net:8651) 모두 해보았는데요 같은 에러가 발생하네요…

뭐가 잘못된건가요?

---

<div class="post-metadata">

**Author:** ![Jamie](https://yyz1.discourse-cdn.com/flex035/user_avatar/devforum.kaia.io/jamie/32/1472_2.png) [@Jamie](https://devforum.kaia.io/u/Jamie)\
**Post date:** [11월 29, 2021, 12:18오전 UTC](https://devforum.kaia.io/t/kip7instance-burn/2570/2 "2021-11-29T00:18:00Z")

</div>

안녕하세요.

`caver.wallet.keyring`은 common architecture 때 생긴 새로운 피처입니다.  
common architecture에서는 이와 함께 호환이 가능한 `caver.kct.kct7`을 제공합니다.  
`caver.klay.KIP7` 대신 `caver.kct.kip7`을 사용하시기 바랍니다.  
`caver.kct.kip7.create(address)` 이렇게 생성하실 수 있습니다.

---

<div class="post-metadata">

**Author:** ![GregSeo](https://yyz1.discourse-cdn.com/flex035/user_avatar/devforum.kaia.io/gregseo/32/2138_2.png) [@GregSeo](https://devforum.kaia.io/u/GregSeo)\
**Post date:** [11월 29, 2021, 3:58오전 UTC](https://devforum.kaia.io/t/kip7instance-burn/2570/3 "2021-11-29T03:58:09Z")

</div>

caver.kct.kip7.create(address) 이렇게 생성을 하면 아래와 같은 에러가 발생하는데요…  
흠… 뭐가 잘못된건가요?

```auto
E:\{path}\node_modules\caver-js\packages\caver-core-method\src\index.js:765
                new Error(`${errors.txErrorTable[txError]}\n ${receiptJSON}`),
                ^

Error: evm: execution reverted
 {
  "blockHash": "0x187c2c4912017f7a650d2b82837e10ec665763462c47dd9e901ae38af9cddb9e",
  "blockNumber": 76590652,
  "contractAddress": null,
  "from": "0x8a86c18c7b289f228315d3ef63f2fb7c00db5dbc",
  "gas": "0x33450",
  "gasPrice": "0x5d21dba00",
  "gasUsed": 24847,
  "input": "0x42966c6800000000000000000000000000000000000000000000000000000000000003e8",
  "logsBloom": "0x00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000",
  "nonce": "0x1f",
  "senderTxHash": "0x03c716760783420ad0caa01e5f6699aad4d304fd3a10a7769dccc2a61baa1fa1",
  "signatures": [
    {
      "V": "0x7f5",
      "R": "0x72572e3b6b8e2ee9d8524ac688805c6764bca25f8be2bae92290b14b71c9870",
      "S": "0x124ed21ded02ce8aa6d817516d22e76bf0660a30475ca5c816221605ef460674"
    }
  ],
  "status": false,
  "to": "0x2fc6d34de2a3faf8a0e24c4239f799ab11ed530d",
  "transactionHash": "0x03c716760783420ad0caa01e5f6699aad4d304fd3a10a7769dccc2a61baa1fa1",
  "transactionIndex": 0,
  "txError": "0x9",
  "type": "TxTypeSmartContractExecution",
  "typeInt": 48,
  "value": "0x0",
  "events": {}
}
    at checkForNormalTx (E:\path\caver\node_modules\caver-js\packages\caver-core-method\src\index.js:765:17)
    at E:\path\caver\node_modules\caver-js\packages\caver-core-method\src\index.js:642:23
    at processTicksAndRejections (node:internal/process/task_queues:96:5)

```

---

<div class="post-metadata">

**Author:** ![Jamie](https://yyz1.discourse-cdn.com/flex035/user_avatar/devforum.kaia.io/jamie/32/1472_2.png) [@Jamie](https://devforum.kaia.io/u/Jamie)\
**Post date:** [11월 30, 2021, 6:35오전 UTC](https://devforum.kaia.io/t/kip7instance-burn/2570/4 "2021-11-30T06:35:36Z")

</div>

위의 에러는 스마트 컨트랙트의 burn을 호출하는 트랜잭션을 실행하는 과정에서 에러가 발생한 경우입니다.  
caver 사용 문법은 정상적으로 동작하나, 왜 burn을 실행하다가 에러가 나는지는 별도의 이슈입니다.  
해당 에러 메세지만으로는 원인분석이 어렵습니다. from 계정이 burn하려는 개수만큼의 토큰을 소유하지 있는지 등을 확인해 주세요.

---

<div class="post-metadata">

**Author:** ![GregSeo](https://yyz1.discourse-cdn.com/flex035/user_avatar/devforum.kaia.io/gregseo/32/2138_2.png) [@GregSeo](https://devforum.kaia.io/u/GregSeo)\
**Post date:** [12월 4, 2021, 5:33오전 UTC](https://devforum.kaia.io/t/kip7instance-burn/2570/5 "2021-12-04T05:33:15Z")

</div>

위의 에러에 관련한 트랜젝션 로그를 보시면  
to 가 컨트랙트 어드레스이며, from이 Creator/Owner 입니다.  
baobab scope에서도 확인해보면 holder가 모든 토큰을 가지고 있는 것으로 나와 있는데요,  
어떤 부분을 확인해야 에러의 내용을 파악할 수 있을까요?

> **[Klaytnscope](https://baobab.scope.klaytn.com/token/0x2fc6d34de2a3faf8a0e24c4239f799ab11ed530d?tabId=tokenHolder)**
>
> Klaytnscope allows you to find data by monitoring network health and statistics of Klaytn as well as profiling blocks and transactions on Klaytn.