I was following This tutorial from Alchemy to build a HelloWorld smart contract.

After successfully deploying it to alchemy, when I wrote the 'Interact.js' script from the tutorial and tried to run it, it got me the following error

my solidity compiler version: 0.8.0

PS E:\programming\Tutorials\Blockchain tutorials\hello world alchemy> npx hardhat run scripts/interact.js

E:\programming\Tutorials\Blockchain tutorials\hello world alchemy\node_modules\@ethersproject\logger\src.ts\index.ts:225
        const error: any = new Error(message);
Error: invalid contract address or ENS name (argument="addressOrName", value=undefined, code=INVALID_ARGUMENT, version=contracts/5.5.0)
    at Logger.makeError (E:\programming\Tutorials\Blockchain tutorials\hello world alchemy\node_modules\@ethersproject\logger\src.ts\index.ts:225:28)
    at Logger.throwError (E:\programming\Tutorials\Blockchain tutorials\hello world alchemy\node_modules\@ethersproject\logger\src.ts\index.ts:237:20)
    at Logger.throwArgumentError (E:\programming\Tutorials\Blockchain tutorials\hello world alchemy\node_modules\@ethersproject\logger\src.ts\index.ts:241:21)
    at Contract.BaseContract (E:\programming\Tutorials\Blockchain tutorials\hello world alchemy\node_modules\@ethersproject\contracts\src.ts\index.ts:706:20)
    at new Contract (E:\programming\Tutorials\Blockchain tutorials\hello world alchemy\node_modules\@ethersproject\contracts\lib\index.js:1047:42)
    at Object.<anonymous> (E:\programming\Tutorials\Blockchain tutorials\hello world alchemy\scripts\interact.js:17:28)
    at Module._compile (node:internal/modules/cjs/loader:1108:14)
    at Object.Module._extensions..js (node:internal/modules/cjs/loader:1137:10)
    at Module.load (node:internal/modules/cjs/loader:988:32)
    at Function.Module._load (node:internal/modules/cjs/loader:828:14)

This is my Smart contract code:

//SPDX-License-Identifier: MIT

pragma solidity ^0.8.0;

contract HelloWorld {
    event UpdatedMessages( string oldStr, string newStr);

    string public message;

    constructor( string memory initMessage ) {
        message = initMessage;

    function update(string memory newMessage) public {
        string memory oldMessage = message;
        message = newMessage;

        emit UpdatedMessages(oldMessage, message);


This is my interact.js code:

const API_KEY = process.env.API_KEY;
const PRIVATE_KEY = process.env.PRIVATE_KEY;
const { ethers } = require("hardhat");
const contract = require("../artifacts/contracts/HelloWorld.sol/HelloWorld.json");

//provider - alchemy
const alchemyProvider = new ethers.providers.AlchemyProvider(
  (network = "goerli"),

//signer - Me
const signer = new ethers.Wallet(PRIVATE_KEY, alchemyProvider);

// contract instance
const helloWorldContract = new ethers.Contract(

const main = async () => {
  const message = await helloWorldContract.message();
  console.log("The message is: " + message);
  console.log("updating the message...");

  const tx = await helloWorldContract.update(
    "This is the new updated message."

  await tx.wait();

  const newMessage = await helloWorldContract.message();
  console.log("The new message is: " + newMessage);

  .then(() => process.exit(0))
  .catch((err) => {

My hardhat.config.js code:

 * @type import('hardhat/config').HardhatUserConfig


const { API_URL, PRIVATE_KEY } = process.env;

module.exports = {
  solidity: "0.8.0",
  defaultNetwork: "goerli",
  networks: {
    hardhat: {},
    goerli: {
      url: API_URL,
      accounts: [`0x${PRIVATE_KEY}`]
  // api key of alchemy
  // wallet password
  • 1
    It seems CONTRACT_ADDRESS is not set correctly, can you log this out in your script, to check that it is correct.
    – Richard
    Jan 25 at 15:38
  • 1
    Hey, @Richard thanks, yep I didn't set up my CONTRACT_ADDRESS properly in my env file. After fixing that, it worked Jan 25 at 17:07

1 Answer 1


Like Richard mentioned in the comments, it seems that CONTRACT_ADDRESS is not set correctly, based on the error you're seeing:

Error: invalid contract address or ENS name

Currently you're pulling CONTRACT_ADDRESS from your .env file. You should be able to fix this problem by updating your environment variable to the correct address.

For example, if this is your .env:

CONTRACT_ADDRESS=0x5180db8f5c931aae63c74266b211f580155ecac8 // double check this address

You should check if the contract address 0x5180db8f5c931aae63c74266b211f580155ecac8 is actually a deployed contract on the Goerli network.

You can use etherscan to check for example: https://goerli.etherscan.io/

If it's not there, then you just need to update with the correct CONTRACT_ADDRESS!

Hope that helps :)

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