使用node.js获取和兑换ERC20token出错

我已经创建了一个自定义ERC20令牌使用openxappelin合同..其他API端点做得很好，但我不能获取或赎回令牌我下面的初始化代码片段

export const client = ipfsHttpClient("http://192.168.0.152:5002");
export const contractaddress = "0x2BbFA7769d2dad0c66a70368b6e5Fc8721085532";

export const provider = new ethers.BrowserProvider("https://eth-sepolia.g.alchemy.com/v2/q1jVC3tLd3_PoadQyMR08osZJ8SDKEqq");

const manager_wallet_private_key = privateKey;
const manager = new ethers.Wallet(manager_wallet_private_key, provider);
export const usercontract = new ethers.Contract(contractaddress, abi, manager);

下面是我的获取令牌路由代码

app.post("/redeem-tokens", async (req, res) => {
  const {address, amount } = req.body;

  try {
      await usercontract.redeemTokens(BigInt(amount),address);
      res.status(200).json({ message: "Tokens redeemed successfully!" });
  } catch (error) {
    console.error(error);
    res.status(500).json({ error: "Internal server error" });
  }
});

app.post("/fetch-tokens", async (req, res) => {
  const {address, amount } = req.body;

  try {
      await usercontract.fetchTokens(BigInt(amount),address);
      res.status(200).json({ message: "Tokens redeemed successfully!" });
  } catch (error) {
    console.error(error);
    res.status(500).json({ error: "Internal server error" });
  }
});

误差

Server is running on 3000
TypeError: unsupported addressable value (argument="target", value=null, code=INVALID_ARGUMENT, version=6.7.1)
    at makeError (file:///E:/ERC20/js-backend/node_modules/ethers/lib.esm/utils/errors.js:113:21)
    at assert (file:///E:/ERC20/js-backend/node_modules/ethers/lib.esm/utils/errors.js:136:15)
    at assertArgument (file:///E:/ERC20/js-backend/node_modules/ethers/lib.esm/utils/errors.js:147:5)
    at resolveAddress (file:///E:/ERC20/js-backend/node_modules/ethers/lib.esm/address/checks.js:112:5)
    at file:///E:/ERC20/js-backend/node_modules/ethers/lib.esm/contract/contract.js:107:24
    at #walkAsync (file:///E:/ERC20/js-backend/node_modules/ethers/lib.esm/abi/fragments.js:581:24)
    at ParamType.walkAsync (file:///E:/ERC20/js-backend/node_modules/ethers/lib.esm/abi/fragments.js:599:24)
    at file:///E:/ERC20/js-backend/node_modules/ethers/lib.esm/contract/contract.js:104:22
    at Array.map (<anonymous>)
    at resolveArgs (file:///E:/ERC20/js-backend/node_modules/ethers/lib.esm/contract/contract.js:103:37) {
  code: 'INVALID_ARGUMENT',
  argument: 'target',
  value: undefined
}

下面的代码

//SPDX-License-Identifier: MIT
pragma solidity ^0.8.17;
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Capped.sol";
import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "./database_helper.sol";

contract Hikiko is ERC20Capped, Ownable, UserDB, ERC20Burnable{ 
    address public Manager;
    
    uint256 public limit = 2000000000 ;
    uint256 public initial_coinbase = 10000000 ; 
    
    constructor() ERC20("Hikiko", "HK") ERC20Capped(limit) Ownable() {
        Manager = msg.sender;
        _mint(Manager, initial_coinbase);
    }

      function _mint(address account, uint256 amount) internal override(ERC20, ERC20Capped) {
        ERC20Capped._mint(account, amount);
    }

    // Allow users to transfer tokens to the Manager when redeeming rewards
    function redeemTokens(uint256 amount,address x) public onlyOwner {
        _transfer(x, Manager, amount);
    }

    // Allow the user to fetch tokens from the contract
    function fetchTokens(uint256 amount,address x) public onlyOwner{
        transfer(x, amount);
    }

    function delete_user(string memory name) public onlyOwner{
        address x= wallets[name].wallet;
        uint256 amount = balanceOf(x);
        _transfer(x, Manager, amount); // Transfer all the amount of tokens before deletion
        burn(amount);//burn the extra tokens
        delete wallets[name];
    }

    // Function to check if minting is needed
    function shouldMintCoins() internal view returns (bool) {
        return balanceOf(Manager) < initial_coinbase / 10;
    }

    // Function to mint coins to the manager
    function additionalcoins() private {
        uint256 a;
        if(shouldMintCoins()==false){ 
            a=0;
        }
        else{
        a = (initial_coinbase / 2) - balanceOf(Manager);
        _mint(Manager,a);
              }
    }

    //Update the wallet address
    function Update_address(string memory name, address data) public onlyOwner{
        address x= wallets[name].wallet;
        uint256 amount = balanceOf(x);
        _transfer(x, data, amount);//Before doing so send the existing tokens to new account
         wallets[name].wallet = data;
    }
    
    function saveUser(address wallet, string memory name, string memory password) public onlyOwner {
        wallets[name].username = name;
        wallets[name].wallet = wallet;
        wallets[name].password = password;
        wallets[name].cid = "default";//The animated smoking gif will be displayed at first
    }

    function Update_password(string memory name, string memory data) public onlyOwner {
        wallets[name].password = data;
    }

    function Update_profile(string memory name, string memory data) public onlyOwner {
        wallets[name].cid = data;
    }

    function Update_mentorship(string memory name) public onlyOwner {
        wallets[name].ismentor = true;
    }

}

我希望将我的自定义令牌发送到用户的帐户我的响应正文中的 Postman { "address": "0x017603449335929525e1eda99f8785207e74A003", "amount": 1200 }

但我得到错误，请告诉我如何修复..

{ "error": "Error Encountered" }