Trying to exchange USDC to ETH vith Uniswap and Ethers, but getting errors all the time.

async function swapUsdcToEth(amount, walledAddress) {
  const usdc = await Fetcher.fetchTokenData(chainId, '0xA0b86991c6218b36c1d19D4a2e9Eb0cE3606eB48');
  const eth = await Fetcher.fetchTokenData(chainId, '0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2');
  const pair = await Fetcher.fetchPairData(usdc, eth);
  const route = new Route([pair], usdc);
  const amountIn = new TokenAmount(usdc, amount);
  const trade = new Trade(route, amountIn, TradeType.EXACT_INPUT);
  const slippageTolerance = new Percent('50', '10000');
  const value = ethers.BigNumber.from(trade.inputAmount.raw.toString()).toHexString();
  const amountOutMin = ethers.BigNumber.from(trade.minimumAmountOut(slippageTolerance).raw.toString()).toHexString();
  const deadline = Math.floor(Date.now() / 1000) + 60 * 20;
  const uniswapRouterV2Address = '0x7a250d5630B4cF539739dF2C5dAcb4c659F2488D';
  const provider = new ethers.providers.JsonRpcProvider('https://mainnet.infura.io/v3/b9fkdmkdkdv4937b52ea9637cf1d1bd');
  const signer = new ethers.Wallet(walledAddress, provider);
  const uniswap = new ethers.Contract(
    uniswapRouterV2Address,
    ['function swapExactTokensForETH(uint amountIn, uint amountOutMin, address[] calldata path, address to, uint deadline) external returns (uint[] memory amounts)'],
    signer
  );
  try {
    const tx = await uniswap.swapExactTokensForETH(value, amountOutMin, [walledAddress], walledAddress, deadline);
    const receipt = await tx.wait();
    console.log('transaction was mined in block', receipt.blockNumber);
  } catch (e) {
    console.log(e);
  }
}

Receiving errors like that: ' Error: cannot estimate gas; transaction may fail or may require manual gas limit '. What I am doing wrong?