Error Interacting with deployed smart contract

Question

I have deployed a simple ERC20 smart contract from open zeppelin in my local blockchain, and I am trying to fetch the balance of account when a user makes a get request to my server with the account address.

Using the account address given by the user, I am trying to get the balance of the account and send it back to the user.

TOKEN SMART CONTRACT IS BELOW:

pragma solidity ^0.8.20;

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Permit.sol";

contract TestToken is ERC20, Ownable, ERC20Permit {
    constructor(address initialOwner)
        ERC20("TestToken", "TTK")
        Ownable(initialOwner)
        ERC20Permit("TestToken")
    {}

    function mint(address to, uint256 amount) public onlyOwner {
        _mint(to, amount);
    }

    function getBalance(address account) public view returns(uint256){
        return(balanceOf(account));
    }
}

SERVER SIDE CODE IS BELOW:

const express = require('express');
const hre = require('hardhat');
var bodyParser = require('body-parser')
const app = express();
const port = 3000;
const contadd = '0x5FbDB2315678afecb367f032d93F642f64180aa3';

async function loadcontract(address){
    const [signer] = await hre.ethers.getSigners();
    const testToken = await hre.ethers.getContractAt('TestToken',contadd,signer);
    const transaction = await testToken.getBalance(address);
    const data = Promise.resolve(transaction);
    return data
}

app.use(bodyParser.urlencoded({ extended: true }));

app.get("/", async (req,res)=>{
    console.log(req.body);
    const address = req.body.address;
    const balance = await loadcontract(address);
    res.send(balance);
});

app.listen(port,()=>{
    console.log(`Server is running on ${port}`);
});

ERROR I AM FACING: When I try to fetch the contract, I am getting the below error.

MY DEPLOY SCRIPT:

let TestToken;
async function main () {
    // We get the contract to deploy
    const [Deployer] = await hre.ethers.getSigners();
    console.log("Deploying contracts with the account:", Deployer.address);
    const DeployerAdd = await Deployer.getAddress();
    TestToken = await hre.ethers.deployContract("TestToken",[DeployerAdd]);
    console.log('TestToken deployed to:', TestToken.address);
  }

main()
  .then(() => process.exit(0))
  .catch(error => {
    console.error(error);
     process.exit(1);
});

I tried debugging this, and seems like the fetching the token balance using the "getBalance" function is causing the issue, but not sure why.

THINGS I HAVE TRIED:

• I made sure the contract is already deployed and I am able to get the contract instance.
• Tried to fetch the balance in my deploy script and it seems to work there, i get a response as big number.

Please let me know if any other information is needed.