Can not deploy smartcontract with truffle and KAS endpoint

I get errors like this when deploying smartcontract by truffle using KAS endpoint. Is there anyone getting error like this.
Used truffle network:

klay_mainnet: {
      provider: () => {
        const option = {
          headers: [
            {
              name: 'Authorization',
              value:
                'Basic ' +
                Buffer.from(accessKeyId + ':' + secretAccessKey).toString('base64'),
            },
            { name: 'x-chain-id', value: '8217' },
          ],
          keepAlive: false,
        }
        return new HDWalletProvider(
          privateKey,
          new Caver.providers.HttpProvider('https://node-api.klaytnapi.com/v1/klaytn', option)
        )
      },
      network_id: 8217, //Klaytn mainnet's network id
      gas: '8000000',
      gasPrice: '750000000000', 
    },

Error:

Error: PollingBlockTracker - encountered an error while attempting to update latest block:
Error: Request failed: Forbidden

Note:

  • accessKeyId/ secretAccessKey: still valid
  • caver-js; 1.6.3 (tried to switch caver-js 1.8 and still get errors)
  • truffle-hdwallet-provider-klaytn: 1.4.2
  • Truffle v5.1.61.

Thanks for your help.

Hmm…
There seems to be no problem in truffle.config-js