Ethers.js : "NONCE EXPIRED" when replacing transaction

Question

I am having this issue when I try to replace a transaction with the same nonce, and higher gas fees. For exemple I use a swap function from a DEX:

const tx1 = await contract.swapExactTokensForTokens( amountIn, amountOutMin, [TokenIn, TokenOut], AddressTo, deadline, {'gasPrice': gasPrice, 'gasLimit': gasLimit})

and then I try to replace the transaction with tx1's nonce:

const tx2 = await contract.swapExactTokensForTokens( amountIn, amountOutMin, [TokenIn, TokenOut], AddressTo, deadline, {'gasPrice': gasPrice+1*10**9, 'gasLimit': gasLimit, 'nonce': tx1.nonce})

After this, I instantly get the nonce_expired error. How can I proceed?

Answer 1

probably, your slippage was too tight, try to set higher amountOutMin. For nonce, you should use web3.utils.toHex(txCount) where txCount is web3.eth.getTransactionCount