corror@CorrorCollins:~/web3-dev/hardhat-simple-storage-test$ npx hardhat verify --network rinkeby 0x2A3a6551B251C199De4748F545799c999b291C71
An unexpected error occurred:
ConnectTimeoutError: Connect Timeout Error
 at onConnectTimeout (/home/corror/web3-dev/hardhat-simple-storage-test/node_modules/undici/lib/core/connect.js:131:24)
 at /home/corror/web3-dev/hardhat-simple-storage-test/node_modules/undici/lib/core/connect.js:78:46
 at Immediate._onImmediate (/home/corror/web3-dev/hardhat-simple-storage-test/node_modules/undici/lib/core/connect.js:119:9)
 at processImmediate (node:internal/timers:466:21) {
 code: 'UND_ERR_CONNECT_TIMEOUT'
}

// SPDX-License-Identifier: MIT
pragma solidity ^0.8.9;
contract SimpleStorage {
 uint256 favoriteNumber;
 mapping(string => uint256) public nametoFavoriteNumber;
 // struct refers to customed object type
 struct People {
 string name;
 uint256 favoritNumber;
 }
 // Syntax of variable initiation: [object type] [visibility] [variable name]
 People[] public people;
 function store(uint256 _favoriteNumber) public {
 favoriteNumber = _favoriteNumber;
 }
 function retrieve() public view returns (uint256) {
 return favoriteNumber;
 }
 function addPerson(string memory _name, uint256 _favoriteNumber) public {
 // The `People` object is: People{}
 // The `People` instance is: People()
 people.push(People(_name, _favoriteNumber));
 nametoFavoriteNumber[_name] = _favoriteNumber;
 }
}

/* Module Requirement */
require("dotenv").config
/**Hardhat Package Usage:
 * 1. ethers: create Factory, deploy contract, wait for confirmation.
 * 2. run: verify contract.
 * 3. network: check configuration */
const { ethers, run, network } = require("hardhat")
/* Main Function */
async function main() {
 /* 1. Deploy Section */
 const SimpleStorageFactory = await ethers.getContractFactory(
 "SimpleStorage"
 )
 console.log("Deploying...")
 const simpleStorage = await SimpleStorageFactory.deploy()
 console.log(`Get Address: ${simpleStorage.address}`)
 console.log("Pending...")
 await simpleStorage.deployed()
 console.log("Deployed!")
 /* 2. Verify Section */
 if (
 process.env.ETHERSCAN_API_KEY &&
 (network.config.chainId === 4 || network.config.chainId === 420)
 ) {
 /**Why we need to wait for a few more block confirmation?
 * 1. EtherScan need a few seconds to find the contract just deployed.
 * 2. We use EtherScan API for verification.
 * So we need to wait EtherScan to find the contract first before we can use it. */
 console.log("Waiting for 6 block confirmation...")
 await simpleStorage.deployTransaction.wait(6)
 console.log("Comfirmed!")
 console.log("Verifying...")
 await verify(simpleStorage.address, [])
 console.log("Verified!")
 }
}
/* Verify Function */
async function verify(contractAddress, args) {
 try {
 /**About "verify:verify":
 * The first verify is a name in the type of string
 * The second verify is the task of verify */
 await run("verify:verify", {
 address: contractAddress,
 constructorArgument: args,
 })
 } catch (e) {
 /**Why we need a try... catch.. here?
 * To throw the error if the verification get wrong. */
 if (e.message.toLowerCase().includes("already verified")) {
 console.log("Already Verified!")
 } else {
 console.log(e)
 }
 }
}
/* Executor Function */
main()
 .then(() => process.exit(0))
 .catch((error) => {
 console.log(error)
 process.exit(1)
 })

const proxyUrl = "http://127.0.0.1:7890" // change to yours, With the global proxy enabled, change the proxyUrl to your own proxy link. The port may be different for each client.
const { ProxyAgent, setGlobalDispatcher } = require("undici")
const proxyAgent = new ProxyAgent(proxyUrl)
setGlobalDispatcher(proxyAgent)

Verifying...
Nothing to compile
NomicLabsHardhatPluginError: Failed to obtain list of solc versions. Reason: connect ECONNREFUSED 127.0.0.1:7890
 at getVersions (/home/corror/web3-dev/hardhat-simple-storage-test/node_modules/@nomiclabs/hardhat-etherscan/src/solc/version.ts:46:11)
 at processTicksAndRejections (node:internal/process/task_queues:96:5)
 at getLongVersion (/home/corror/web3-dev/hardhat-simple-storage-test/node_modules/@nomiclabs/hardhat-etherscan/src/solc/version.ts:17:20)
 at SimpleTaskDefinition.verifySubtask [as action] (/home/corror/web3-dev/hardhat-simple-storage-test/node_modules/@nomiclabs/hardhat-etherscan/src/index.ts:293:7)
 at Environment._runTaskDefinition (/home/corror/web3-dev/hardhat-simple-storage-test/node_modules/hardhat/src/internal/core/runtime-environment.ts:219:14)
 at Environment.run (/home/corror/web3-dev/hardhat-simple-storage-test/node_modules/hardhat/src/internal/core/runtime-environment.ts:131:14)
 at verify (/home/corror/web3-dev/hardhat-simple-storage-test/scripts/deploy.js:56:9)
 at main (/home/corror/web3-dev/hardhat-simple-storage-test/scripts/deploy.js:36:9)
 Caused by: Error: connect ECONNREFUSED 127.0.0.1:7890
 at TCPConnectWrap.afterConnect [as oncomplete] (node:net:1157:16)