Error: call revert exception

[ms-peter-son]

Hi teams.

I followed up your document but i got the issue like below picture

//harhat.config.ts

import * as dotenv from "dotenv";

import { HardhatUserConfig, task } from "hardhat/config";
import "@nomiclabs/hardhat-etherscan";
import "@nomiclabs/hardhat-waffle";
import "@typechain/hardhat";
import "hardhat-gas-reporter";
import "solidity-coverage";

import "@nomiclabs/hardhat-ethers";
import "hardhat-deploy-ethers";
import "hardhat-deploy";
import "@symfoni/hardhat-react";
import "@typechain/ethers-v5";

dotenv.config();

// This is a sample Hardhat task. To learn how to create your own go to
// https://hardhat.org/guides/create-task.html
task("accounts", "Prints the list of accounts", async (taskArgs, hre) => {
  const accounts = await hre.ethers.getSigners();

  for (const account of accounts) {
    console.log(account.address);
  }
});

// You need to export an object to set up your config
// Go to https://hardhat.org/config/ to learn more

const config: HardhatUserConfig = {
  solidity: "0.8.4",
  networks: {
    ropsten: {
      // url: process.env.ROPSTEN_URL || "",
      url: "https://api.baobab.klaytn.net:8651",
      accounts:
        process.env.PRIVATE_KEY !== undefined ? [process.env.PRIVATE_KEY] : [],
    },
  },
  gasReporter: {
    enabled: process.env.REPORT_GAS !== undefined,
    currency: "USD",
  },
  etherscan: {
    apiKey: process.env.ETHERSCAN_API_KEY,
  },
};

export default config;

I set up the config at the hardhat.config.ts

I tried to follow up your hardhat-react-boilerplate repo. But i got the same issue.

And then i searched at the google about it, there are same problem like me. To solve it, it is likely network issue.

How can i solve the issue?