How to get transaction approval for Polygon network

[Jithendra-transfi]

const WMATIC_TOKEN = new Token(
ChainId.POLYGON,
"0x0d500B1d8E8eF31E21C99d1Db9A6444d3ADf1270",
18,
"WMATIC",
"Wrapped Matic"
);

const USDC_TOKEN = new Token(
ChainId.POLYGON,
"0x2791Bca1f2de4661ED88A30C99A7a9449Aa84174",
6,
"USDC",
"USD Coin"
);

const CurrentConfig = {
rpc: {
mainnet:
"https://polygon-mainnet.infura.io/v3/2945612d95e74e4f82e05d4fbf00db6c",
},
tokens: {
in: USDC_TOKEN,
amountIn: 25,
out: WMATIC_TOKEN,
poolFee: FeeAmount.MEDIUM,
},
};

const sendTransaction = async (transaction) => {
if(transaction.value){
transaction.value = BigNumber.from(transaction.value)
}

const txRes = await wallet.sendTransaction(transaction);  // getting error over here
if(txRes){
    console.log('Hurrey')
}else{
    console.log('Hell')
}
let receipt = null
const provider = getProvider();
while(receipt === null){
 try {
     receipt = await provider.getTransactionReceipt(txRes.hash)
     if(receipt === null){
         continue
     }
 } catch (error) {
     console.log(`Receipt error:`, error)
   break
 }
}
if(receipt){
 console.log('Transaction Sent')
 return true;
}else{
 console.log('Transaction Failed')
 return null;
}

}

const getTokenTransferApproval = async (token) => {
const provider = getProvider();
const address = getWalletAddress();

if (!provider || !address) {
console.log("please check provider or walletAddress");
}
try {
const tokenContract = new ethers.Contract(
token.address,
ERC20_ABI,
provider
);

const transaction = await tokenContract.populateTransaction.approve(
    SWAP_ROUTER_ADDRESS,
    fromReadableAmount(
      TOKEN_AMOUNT_TO_APPROVE_FOR_TRANSFER,
      token.decimals
    ).toString()
  )

const resp = await sendTransaction({
  ...transaction,
  from: address,
});

return resp;

} catch (e) {
console.log(e);
console.log('approval failed')
}
};

const tokenApproval = await getTokenTransferApproval(CurrentConfig.tokens.in);

getting error as follow:

Error: transaction underpriced
at /Users/jithendrakumar/Desktop/uniswap/new-uniswap1/node_modules/@ethersproject/providers/lib/json-rpc-batch-provider.js:72:41
at Array.forEach ()
at /Users/jithendrakumar/Desktop/uniswap/new-uniswap1/node_modules/@ethersproject/providers/lib/json-rpc-batch-provider.js:69:27
at process.processTicksAndRejections (node:internal/process/task_queues:95:5) {
code: -32000,
data: undefined,
transaction: {
type: 2,
chainId: 137,
nonce: 21,
maxPriorityFeePerGas: BigNumber { _hex: '0x59682f00', _isBigNumber: true },
maxFeePerGas: BigNumber { _hex: '0x6a0d032ab4', _isBigNumber: true },
gasPrice: null,
gasLimit: BigNumber { _hex: '0xb41d', _isBigNumber: true },
to: '0x0d500B1d8E8eF31E21C99d1Db9A6444d3ADf1270',
value: BigNumber { _hex: '0x00', _isBigNumber: true },
data: '0x095ea7b3000000000000000000000000e592427a0aece92de3edee1f18e0157c0586156400000000000000000000000000000000000000000001a784379d99db42000000',
accessList: [],
hash: '0x8a40ff615225b916935ceb17e2098b7ff178ef1d24b5ff1ad0bb10d7dd1c693f',
v: 0,
r: '0x0ddf0e88ae53876d4d2d70a556bc25bffab46533ac19ebf75b8150c349c74ebd',
s: '0x6c2ec585a1c12c094bfc7c75b735749cbae97e3056e70de0f1837ae0aba8ee3b',
from: '0xaDe56237C3b7d4E000641eA0484dC9B44B9d366f',
confirmations: 0
},
transactionHash: '0x8a40ff615225b916935ceb17e2098b7ff178ef1d24b5ff1ad0bb10d7dd1c693f'
}