current position:Home>Fail with error 'TransferHelper: TRANSFER_ FROM_ FAILED'

Fail with error 'TransferHelper: TRANSFER_ FROM_ FAILED'

2022-02-03 23:23:18 Q & A of Denglian community

test dai exchange eth When , Encounters an error Fail with error 'TransferHelper: TRANSFER_FROM_FAILED' Use uniswapV2Router.swapExactTokensForETH stay swap Before , Authorization has been made require(dai.approve(address(uniswapV2Router), amountIn), 'approve failed.') Why do you report such errors ?






Other answers 1:

copyright notice
author[Q & A of Denglian community],Please bring the original link to reprint, thank you.
https://en.netfreeman.com/2022/02/202202032323165146.html

Random recommended