'TransactionError when using Brownie on Optimism - Tx dropped without known replacement

I have a Python script using Brownie that occasionally triggers a swap on Uniswap by sending a transaction to Optimism Network.

It worked well for a few days (did multiple transactions successfully), but now each time it triggers a transaction, I get an error message:

TransactionError: Tx dropped without known replacement

Complete error message

However, the transaction goes through and get validated, but the script stops.

swap_router = interface.ISwapRouter(router_address)

params = (
            weth_address,
            dai_address,
            3000,
            account.address,
            time.time() + 86400,
            amount * 10 ** 18,
            0,
            0,
        )

amountOut = swap_router.exactInputSingle(params, {"from": account})

Solution 1:^[1]

There is a possibility that one of your methods seeks data off-chain and is being called prematurely before the confirmation is received. I had the same problem, and I managed to sort it out by adding

time.sleep(60)

at the end of the function that seeks for data off-chain

Solution 2:^[2]

"Dropped and replaced" means the transaction is being replaced by a new one, Eth is being overloaded with a new gas fee. My guess is that you need to increase your gas costs in order to average the price.

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution	Source
Solution 1	Martin Maati
Solution 2	Matthew Segura

'TransactionError when using Brownie on Optimism - Tx dropped without known replacement

Solution 1:[1]

Solution 2:[2]

Sources

Related Questions

Solution 1:^[1]

Solution 2:^[2]