Merkle Tree Airdrop ERC20 tokens claim from Remix?

Smart Contracts
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1

I want to airdrop ERC20 tokens through Merkle tree airdrop and I created the root hash and got the Merkleproof for one of the addresses. Still, while claiming manually from remix it's showing ""message": "execution reverted: ERC20: insufficient allowance" allowance error."

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.8.0;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/IERC20.sol";
import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/utils/cryptography/MerkleProof.sol";
contract MerkleDistributor{
    address public immutable  token;
    bytes32 public immutable  merkleRoot;
    uint256 public dropAmount;
    address public owner;

    // This is a packed array of booleans.
    mapping(address => bool) public whitelistClaimed;

    constructor(address token_, bytes32 merkleRoot_,uint256 dropAmount_)  {
        token = token_;
        merkleRoot = merkleRoot_;
        dropAmount = dropAmount_;
        owner = msg.sender;
    }


    function claim( bytes32[] calldata merkleProof) external  {

        //Basic data validation to ensure that wallet hasn't Claimed
        require(!whitelistClaimed[msg.sender] ,  'MerkleDistributor: Drop already claimed.');

        // Verify the merkle proof.
        bytes32 leaf = keccak256(abi.encodePacked(msg.sender));
        require(MerkleProof.verify(merkleProof, merkleRoot, leaf), 'MerkleDistributor: Invalid proof.');

        // Mark it claimed and send the token.
        whitelistClaimed[msg.sender] = true;
        require(IERC20(token).transferFrom(owner , msg.sender, dropAmount), 'MerkleDistributor: Transfer failed.');

    }
}

this was the airdrop code,

pragma solidity ^0.8.0;

import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC20/ERC20.sol";

contract CryptoNix is ERC20 {
   address public owner;
   constructor()ERC20 ("CryptoNix" , "CNX"){

      owner = msg.sender;
      
_mint(msg.sender , 10000000000000000000000);
   } 
}

This was the token code,

image
image383×680 27.8 KB

I gave the approval also still showed an allowance error.

Please help with how can users can claim airdrop tokens from the remix.

2

You may be giving approval to the wrong address.

3

Do I have to give the approval to the Merkle tree contract address because I am calling the transferFrom function from the Merkle contract?

4

@Gopalgurram Yes, that's right!