Transaktion wurde während der Vertragsausführung rückgängig gemacht [Rückgängig gemacht]

Ich habe ETH an eine Vertragsadresse gesendet, und die Transaktion ist "fehlgeschlagen" und sagt: Warning! Error encountered during contract execution [Reverted].

Vertragsadresse und Transaktionsfehler hier:

https://rinkeby.etherscan.io/tx/0x28a0a0f7eb8cf863afb4a9a2425648d2d9693e39793f0f9cc01d006374808370

ICO-Token-Vertragscode:-

pragma solidity ^0.4.24;
import "./DappToken.sol";


contract ICOToken is DappToken {

   string public name = 'ICOToken';
   string public symbol = 'ITK';
   uint256 public decimals = 18;
   uint256 public totalSupply;
   address public crowdsaleAddress;
   address public owner;
   uint256 public ICOEndTime = 1541246755;
   uint256 public balance;

   modifier onlyCrowdsale {
      require(msg.sender == crowdsaleAddress);
      _;
   }

   modifier onlyOwner {
      require(msg.sender == owner);
      _;
   }

//   modifier afterCrowdsale {
//  require(now > ICOEndTime || msg.sender == crowdsaleAddress);
//      _;
//  }

   constructor (uint256 _tokenSupply) public DappToken() {
      totalSupply = _tokenSupply;
      balanceOf[msg.sender] = _tokenSupply;
      owner = msg.sender;
   }


   function setCrowdsale(address _crowdsaleAddress) public onlyOwner  {

      require(_crowdsaleAddress != address(0));
      crowdsaleAddress = _crowdsaleAddress;

   }


    function buyTokens(address _receiver, uint256 _amount) public  {

      require(_receiver != address(0));
      require(_amount > 0);
      transfer(_receiver, _amount);


   }

//       /// @notice Override the functions to not allow token transfers until the end of the ICO
//   function transfer(address _to, uint256 _value) public afterCrowdsale returns(bool) {

//       return super.transfer(_to, _value);

//   }


//   /// @notice Override the functions to not allow token transfers until the end of the ICO
//   function transferFrom(address _from, address _to, uint256 _value) public afterCrowdsale returns(bool) {

//       return super.transferFrom(_from, _to, _value);

//   }


//   /// @notice Override the functions to not allow token transfers until the end of the ICO
//   function approve(address _spender, uint256 _value) public afterCrowdsale returns(bool) {

//       return super.approve(_spender, _value);
//   }

//   /// @notice Override the functions to not allow token transfers until the end of the ICO

//   function increaseApproval(address _spender, uint _addedValue) public afterCrowdsale returns(bool success) {

//       return super.increaseApproval(_spender, _addedValue);
//   }

//   /// @notice Override the functions to not allow token transfers until the end of the ICO

//   function decreaseApproval(address _spender, uint _subtractedValue) public afterCrowdsale returns(bool success) {

//       return super.decreaseApproval(_spender, _subtractedValue);
//   }

//   function emergencyExtract() external onlyOwner {

//       owner.transfer(address(this).balance);
//   }

}

Crowdsale-Vertragscode wie folgt:-

    pragma solidity ^0.4.24;
import "./ICOToken.sol";

contract Crowdsale {
   bool public icoCompleted;
   uint256 public icoStartTime = 1538567825; // 3 oct 2018 11.57 AM UTC;
   uint256 public icoEndTime = 1541246755;  // 3 nov 2018 11.57 Am UTC;
   uint256 public tokenRate;
   uint256 public fundingGoal;
   address public owner;
   ICOToken public token;
   uint256 public tokensRaised;
   uint256 public etherRaised;
   uint256 public etherUsed = msg.value;
   uint256 public tokensToBuy;


   modifier whenIcoCompleted {
      require(icoCompleted);
      _;
   }

    modifier onlyOwner {
      require(msg.sender == owner);
      _;
   }

   function () public payable {
       buy();
   }

     constructor(uint256 _tokenRate, address _tokenAddress, uint256 _fundingGoal) public {
      require(icoStartTime != 0 &&
      icoEndTime != 0 &&
      icoStartTime < icoEndTime &&
      _tokenRate != 0 &&
      _tokenAddress != address(0) &&
      _fundingGoal != 0);
      tokenRate = _tokenRate;
      token = ICOToken(_tokenAddress);
      fundingGoal = _fundingGoal;
      owner = msg.sender;
      etherUsed;
      tokensToBuy;
   }

    function buy() public payable {

    //   require(tokensRaised < fundingGoal);
    //   require(now < icoEndTime && now > icoStartTime);

      etherUsed = msg.value;

      tokensToBuy = etherUsed * (10 ** token.decimals()) / 1 ether * tokenRate;

    //   Check if we have reached and exceeded the funding goal to refund the exceeding tokens and ether

    //   if(tokensRaised + tokensToBuy > fundingGoal) {

    //      uint256 exceedingTokens = tokensRaised + tokensToBuy - fundingGoal;
    //      uint256 exceedingEther;

    // //   Convert the exceedingTokens to ether and refund that ether
    //      exceedingEther = exceedingTokens * 1 ether / tokenRate / token.decimals();

    //      msg.sender.transfer(exceedingEther);

    //     //   Change the tokens to buy to the new number
    //      tokensToBuy -= exceedingTokens;

    //     //   Update the counter of ether used
    //      etherUsed -= exceedingEther;

    //   }
      // Send the tokens to the buyer
      token.buyTokens(msg.sender, tokensToBuy);

      // Increase the tokens raised and ether raised state variables
      tokensRaised += tokensToBuy;
      etherRaised += etherUsed;
   }


   function extractEther() public whenIcoCompleted onlyOwner {
       owner.transfer(address(this).balance);
   }

}

Ich habe auch Remix debuggt und festgestellt, dass dieser msg.value nicht in der Etherused-Variablen gespeichert wird, die im Crowdsale Smart Contract verwendet wird, wenn der Endbenutzer den Betrag per Metamask-Wallet bezahlt. Das Token kann also nicht an den Empfänger übertragen werden.

Also wie kann ich dieses Problem lösen?? Bitte hilf mir.

Danke.