I followed this tutorial https://www.youtube.com/watch?v=rd0TTLjQLy4&t=1247s and it works almost perfectly. However, when I input over 0.00000001 eth or 10000000000 wei, there is an error and it says that the transaction is expected to fail. Does anybody know the reason of this error?
that could mean that there is not enough funds in the contract to pay and the function will exit at a require, usually it means that an exception will be generated at that contract execution
Oh thanks I got it, I needed to fund my contract!