After all attempts to verify the smart contract, i keep getting PaserError - not found: File import callback not supported

Question

This is the issue: ParserError: Source "@openzeppelin/contracts/access/Ownable.sol" not found: File import callback not supported. Showing a picture below. It's on bscscan between to verify. The error says it is trying to open a file with "@openzeppelin/contracts/..." and it can't find it. The thing is, how do I make it so it can find it? If that would be the case.

This is my contract (changed the token name for security reasons):

pragma solidity ^0.8.0;

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

contract secret is ERC20 { constructor(uint256 initialsupply) public ERC20 ("secret", "secret") { _mint(msg.sender, initialsupply); } }

And when i verify it on bscscan i keep getting this. I have actually not much idea what to do now to fix this issue, would be really great if someone could give me an advice to solve this issue.

Answer 1

Check out this page https://docs.openzeppelin.com/contracts/4.x/

First you do: $ npm install @openzeppelin/contracts

And then import ERC20.sol like: import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

Answer 2

If you are deploying through remix after importing OZ contracts, you need to flatten them in order to verify : https://forum.openzeppelin.com/t/verify-erc20-token-on-etherscan-that-was-deployed-through-remix-step-by-step-guide/9051