Possible Causes of the Error

Oct 13, 2025 by wbrum.org 116 views

Introduction

When working with decentralized applications (dApps) and smart contracts, errors can be frustrating and time-consuming to resolve. One common error that developers encounter is the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution. This error can occur when interacting with a contract, such as the Uniswap exchange protocol, and can be caused by various factors. In this article, we will discuss the possible causes of this error and provide guidance on how to resolve it.

Understanding the Error

The UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error is a warning that indicates a promise was rejected, but the error was not handled. This can occur when a transaction is executed on the Ethereum Virtual Machine (EVM) and is reverted due to a contract execution error. The EVM is a virtual machine that executes smart contracts on the Ethereum blockchain.

Possible Causes of the Error

There are several possible causes of the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error. Some of the most common causes include:

Insufficient funds: If the user does not have sufficient funds to execute a transaction, the EVM will revert the transaction.
Invalid transaction data: If the transaction data is invalid or malformed, the EVM will revert the transaction.
Contract execution error: If there is an error in the contract execution, such as a division by zero or an out-of-gas error, the EVM will revert the transaction.
Gas limit exceeded: If the gas limit is exceeded, the EVM will revert the transaction.

Resolving the Error

To resolve the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error, you can try the following:

Check the transaction data: Verify that the transaction data is valid and well-formed.
Check the contract execution: Verify that the contract execution is correct and does not contain any errors.
Increase the gas limit: If the gas limit is exceeded, try increasing the gas limit to allow the transaction to execute.
Check the user's funds: Verify that the user has sufficient funds to execute the transaction.

Example Code

Here is an example of code that exchanges ETH with DAI using the ethToTokenSwapInput function from the Uniswap exchange protocol:

const Web3 = require('web3');
const uniswap = require('@uniswap/sdk');

const web3 = new Web3(new Web3.providers.HttpProvider('https://rinkeby.infura.io/v3/YOUR_PROJECT_ID'));

const tokenA = uniswap.Token.list('0x6B175474E89094C44Da98b954EedeAC495271d0F');
const tokenB = uniswap.Token.list('0x8f3Cf7c6Bf1B497aeEB6c239FciJJB70a1a1DCa9');

const amountIn = web3.utils.toWei('1', 'ether');
const amountOut = await uniswap.ethToTokenSwapInput(tokenA, tokenB, amountIn);

console.log(amountOut);

Troubleshooting

If you are still experiencing issues with the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error, you can try the following:

Check the console output: Verify that the console output is not showing any errors.
Check the transaction hash: Verify that the transaction hash is correct and not reverted.
Check the contract execution: Verify that the contract execution is correct and does not contain any errors.

Conclusion

The UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error can be caused by various factors, including insufficient funds, invalid transaction data, contract execution errors, and gas limit exceeded. To resolve this error, you can try checking the transaction data, contract execution, and user's funds. Additionally, you can try increasing the gas limit to allow the transaction to execute. By following the steps outlined in this article, you should be able to resolve the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error and successfully execute transactions on the Ethereum blockchain.

Additional Resources

Resolving the Error: Transaction has been reverted by the EVM in the contract execution Error
Troubleshooting Smart Contract Execution Errors
Q&A: Resolving the UnhandledPromiseRejectionWarning: Error: Transaction Has Been Reverted by the EVM in the Contract Execution ===========================================================

Introduction

In our previous article, we discussed the possible causes of the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error and provided guidance on how to resolve it. In this article, we will answer some frequently asked questions (FAQs) related to this error.

Q: What is the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error?

A: The UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error is a warning that indicates a promise was rejected, but the error was not handled. This can occur when a transaction is executed on the Ethereum Virtual Machine (EVM) and is reverted due to a contract execution error.

Q: What are the possible causes of the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error?

A: The possible causes of the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error include:

Insufficient funds
Invalid transaction data
Contract execution error
Gas limit exceeded

Q: How can I resolve the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error?

A: To resolve the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error, you can try the following:

Check the transaction data
Check the contract execution
Increase the gas limit
Check the user's funds

Q: What is the difference between a transaction and a contract execution?

A: A transaction is a single operation that is executed on the Ethereum blockchain, such as sending Ether or executing a smart contract function. A contract execution, on the other hand, is the execution of a smart contract's code, which can involve multiple transactions.

Q: How can I increase the gas limit to resolve the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error?

A: To increase the gas limit, you can use the gas parameter when calling the ethers library's send function. For example:

const ethers = require('ethers');

const provider = new ethers.providers.JsonRpcProvider('https://rinkeby.infura.io/v3/YOUR_PROJECT_ID');
const contract = new ethers.Contract('0x...');

const gas = 1000000; // Increase the gas limit to 1 million
contract.functions.myFunction().send({ gas });

Q: How can I check the user's funds to resolve the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error?

A: To check the user's funds, you can use the ethers library's getBalance function. For example:

const ethers = require('ethers');

const provider = new ethers.providers.JsonRpcProvider('https://rinkeby.infura.io/v3/YOUR_PROJECT_ID');
const userAddress = '0x...';

const balance = await provider.getBalance(userAddress);
console.log(balance);

Q: What are some best practices for resolving the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error?

A: Some best practices for resolving the UnhandledPromiseRejectionWarning: Error: Transaction has been reverted by the EVM in the contract execution error include:

Always check the transaction data and contract execution before executing a transaction
Increase the gas limit as needed to prevent transaction reverts
Check the user's funds before executing a transaction
Use a try-catch block to handle any errors that may occur during transaction execution