Ethereum swap accurate tokens for error tokens: Transfer_from_failed even after approval
As an Ethereum user, you are probably familiar with the popular UNISWAP V2 protocol, which allows for a change of two types of token and any other token) without the need to transfer one of them from your wallet. However, sometimes the mistakes that prevent this change procedure occur, including the infamous “transfer from failed” mistake after approval.
In this article we will be carried out in the possible causes behind this error and explore ways to solve it.
What is Swapexactokensfortukens?
SwapexacttokensFortokens is an Ethereum protocol used to replace the token. Similar to the Uniswap V2, but instead of replacing two token, it allows you to replace one secret (ETX) with one or more other tokens (TX). This can be useful when ETX is used as collateral in borrowing mechanisms.
Why does SwapexactoKensfortukens error appear?
Error “Transfer from Failed” usually occurs when the following conditions are fulfilled:
- The user approved a replacement contract.
- You have sufficient Exactoken balance to transfer.
- You are trying to pull ETX from your wallet (even if it is not your primary wallet).
If any of these conditions are not fulfilled, the replacement will succeed.
Possible solutions
To solve the “Transfer from Failed” error, try the following:
1. Make sure you approved the contract
Make sure you have successfully approved the SWAPEXACTKENSOBENSOBENS contract using the function of SwapexactokensFortokens' at your local node.
strength
Pragma Solidity ^0.8.0;
MYSWAPCONTRAT {Treaty
SWAPEXACTKETKETKETKENKENS FUNCTION (Address _to, NAint256 amount, address [] Memory _tokens, Rok NAint256)
// Logic of approval here …
Iche
Iche
`
2. Check your Exactoken balance
Ensure you have enough ETX to transfer.
strength
Pragma Solidity ^0.8.0;
MYSWAPCONTRAT {Treaty
mapping (address => nint256) public etxbalance;
GETBALANCE FUNCTION (Address _user) Public display returns (nint256) {
return ETXBALANCE [_USER];
Iche
Iche
`
3. Make sure your ETX is sent to a contract
Make sure your ETX is truly transferred from your wallet to the SWAPEXACTKETKETKETOKENS contract.
strength
Pragma Solidity ^0.8.0;
MYSWAPCONTRAT {Treaty
mapping (address => nint256) public etxbalance;
mapping (address => address) Public txssent;
Transferetx Function (address _user, address _to, nint256 amount) Public Payment {
// Add logic here …
Iche
Iche
``
4. Wait to get rid of the “Transfer from Failed”
If you still have problems, try to wait a few hours and make sure the problem is solved.
Conclusion
The “Transfer from Failed” Error may occur for various reasons, including insufficient balance or approval at your local node. By checking your ETX Salda, by checking the logic of approval and providing an ETX sent to a replacement contract, you should be able to solve this problem. If the problem continues, it is recommended to wait a few hours before trying to replace again.
additional resources
For more information on the use and solving problems with the Ethereum protocol, see:
- [Ethereum.org] (
- [Uniswap V2 Documentation] (