Error sending Ether to sales contract


I have the following case. Create an ERC20 mint token with the following code.

pragma solidity ^0.6.5;

import "@openzeppelin/contracts/access/AccessControl.sol";
import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

contract MyToken is ERC20, AccessControl {

    bytes32 public constant MINTER_ROLE = keccak256("MINTER_ROLE");
    bytes32 public constant BURNER_ROLE = keccak256("BURNER_ROLE");

    constructor() public ERC20("MyToken", "TKN") {
        _setupRole(DEFAULT_ADMIN_ROLE, msg.sender);

    function mint(address to, uint256 amount) public {
        require(hasRole(MINTER_ROLE, msg.sender), "Caller is not a minter");
        _mint(to, amount);

    function burn(address from, uint256 amount) public {
        require(hasRole(BURNER_ROLE, msg.sender), "Caller is not a burner");
        _burn(from, amount);

Address that takes me in testnet is: 0x7823549A14ab83d50B6654336A42Bb679A695875

Then create a sales contract with the following code:

pragma solidity ^0.5.0;

import "@openzeppelin/contracts/crowdsale/Crowdsale.sol";
import "@openzeppelin/contracts/crowdsale/emission/MintedCrowdsale.sol";
import "@openzeppelin/contracts/crowdsale/validation/CappedCrowdsale.sol";
import "@openzeppelin/contracts/crowdsale/validation/TimedCrowdsale.sol";
import "@openzeppelin/contracts/crowdsale/distribution/PostDeliveryCrowdsale.sol";
import "@openzeppelin/contracts/crowdsale/price/IncreasingPriceCrowdsale.sol";

contract DappTokenCrowdsale is Crowdsale, MintedCrowdsale, CappedCrowdsale, TimedCrowdsale, PostDeliveryCrowdsale, IncreasingPriceCrowdsale {
  mapping(address => uint256) public contributions;
    uint256 _rate,
    address payable _wallet,
    uint256 _cap,
    uint256 _openingTime,
    uint256 _closingTime,
    uint256 _initialRate,
    uint256 _finaleRate,
    IERC20 _token
    Crowdsale(_rate, _wallet, _token)    
    TimedCrowdsale(_openingTime, _closingTime)
    IncreasingPriceCrowdsale (_initialRate, _finaleRate)

  function getUserContribution(address _beneficiary)
    public view returns (uint256)
    return contributions[_beneficiary];

The parameters I use are the following:

const DappTokenCrowdsale = artifacts.require("DappTokenCrowdsale");
 let rate = 400;
 let wallet = "0x56679A0bD8a24007aD5cBBd4375179c3A81C9319";
 let cap = 50000000000000000000n;
 let openTime = 1605207911; //    //Epoch Unix Time Stamp 
 let closeTime =  1605218711; //    //Epoch Unix Time Stamp 
 let initialRate = 400;
 let finalRate = 50;
 let toke =  "0x7823549A14ab83d50B6654336A42Bb679A695875"; 
module.exports = function(_deployer) {
     _deployer.deploy(DappTokenCrowdsale, rate, wallet, cap, openTime, closeTime, initialRate, finalRate, toke);

Then in the token contract I gave it MINTER_ROLE permissions from the grantRole function so that it can token the sale contract.

Now when I want to test, I know that the sale is open, I try to send 1 ETH to the sale contract from metamak, it generates an error.

Is there anything else I need to do? Could you give me any suggestions please.

1 Like

Which test net do you use? and what is the error message?

1 Like

hi @Skype

The test network is ropsten

This is the transaction:

1 Like

The error message is out of gas, so maybe you can increase the gasLimit and then have a try.

1 Like

Increase the gas and now I have another error

1 Like

Hi @jeissoni,

I assume that your timed crowdsale had ended, so you may want to redeploy.

You could interact using the console to check the state:

You could check the values of hasClosed or isOpen.

You may want to call buyTokens rather than just sending Ether to the crowdsale.

Hi @abcoathup

I deployed a new contract, I am sure the purchase is open. But I get the same error referring to @Skyge.

The use of the buyTokens method, I honestly don’t get it. The parameter is only one and it is of type address, so where is the amount of ether sent received?

1 Like

Could you please verify your contract on the etherscan, so I have a try by myself.

1 Like

Hi @Skyge

I created a new sales contract, already verified

The address in ropsten is: 0x8e03c66A937EE34da727C0Bf8ceB26254801fd24

1 Like

Hey, I think at about line 1908:

            ERC20Mintable(address(token())).mint(beneficiary, tokenAmount),
                "MintedCrowdsale: minting failed"

The token is Tress, and at the line 1315 in the Tress token contract:

function mint(address to, uint256 amount) public {
        require(hasRole(MINTER_ROLE, msg.sender), "Caller is not a minter");
        _mint(to, amount);

So you can find out that there is not a return value for mint, so I think the problem is at there.

1 Like

Hi @jeissoni,

It looks like @Skyge has spotted the issue. :pray:
You can extend the crowdsale to change the minting. I recommend creating unit tests to test this.