Cannot verify and publish example contract

Support Contracts
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1

Good morning.
I've tried to deploy and then verify multiple smart contracts with Truffle and Remix combined (I'm a bit newbie about publishing ad verifying).
I've deployed the contract with Remix and then verified and published using the plugin "truffle-verify-plugin" version 0.6.3, but I've got a weird error when I've tried to publish and verify this smart contract:

:1234: Code to reproduce

// contracts/GameItem.sol
// SPDX-License-Identifier: MIT
pragma solidity ^0.8.0;

import "@openzeppelin/contracts/token/ERC721/extensions/ERC721URIStorage.sol";
import "@openzeppelin/contracts/utils/Counters.sol";

contract GameItem is ERC721URIStorage {
    using Counters for Counters.Counter;
    Counters.Counter private _tokenIds;

    constructor() ERC721("GameItem", "ITM") {}

    function awardItem(address player, string memory tokenURI)
        public
        returns (uint256)
    {
        uint256 newItemId = _tokenIds.current();
        _mint(player, newItemId);
        _setTokenURI(newItemId, tokenURI);

        _tokenIds.increment();
        return newItemId;
    }
}



Result of the verification with the plugin:

npx truffle run verify GameItem@0xBe4399464008a98DF93c3f19c98781C842Bb6617 --network moonbase
Verifying contracts on moonscan
   Verifying GameItem@0xBe4399464008a98DF93c3f19c98781C842Bb6617
   Fail - Unable to verify
   Failed to verify 1 contract(s): GameItem@0xBe4399464008a98DF93c3f19c98781C842Bb6617
Verifying contracts on sourcify
   Verifying GameItem@0xBe4399464008a98DF93c3f19c98781C842Bb6617
   Fail - Unable to verify: The deployed and recompiled bytecode don't match.
   Failed to verify 1 contract(s): GameItem@0xBe4399464008a98DF93c3f19c98781C842Bb6617

:computer: Environment

My specs for this attempt are:

Truffle v5.8.1 (core: 5.8.1)
Solidity v0.5.16 (solc-js)
Node v18.15.0
Remix online version

I've compiled the contract with 0.8.9 compiler on both Remix and Truffle but there was a different result in the compilation and so I wasn't able to verify the contract with Truffle.

I've tried the same approach with contracts provided by the OZ wizard and there are no problems.
What can be the failing reason?

Thanks for your availability!

2

Make sure that all of your compiler parameters are configured for your unsuccessful verification attempt in the same way that they were configured for your successful compilation attempt.

For example:

{
    version: '0.8.9',
    viaIR: false,
    settings: {
        optimizer: {
            enabled: true,
            runs: 200
        }
    }
}
3

Yeah, on Remix I've not added the optimization and this is my configuration in Truffle:

// Configure your compilers
  compilers: {
    solc: {
      version: "0.8.13",      // Fetch exact version from solc-bin
    }
  }
4

You probably wanna make up your mind exactly on how you're compiling the contract, and then make sure that you specify the exact same configuration when you're verifying it.

5

I've tried indeed with the same version, so 0.8.9, (sorry the reply above I've written the code about my last attempt with another compiler version), but the same result.

6

The implicit (default) configuration on Remix might be different from your explicit configuration on Truffle. For example, it might include:

        optimizer: {
            enabled: true,
            runs: 200
        }
7

Screenshot 2023-05-28 alle 21.29.28
Screenshot 2023-05-28 alle 21.29.28702×1138 53.4 KB

This was the configuration, it seems to match...

8

Dude, there is no contract deployed at that address on ethereum mainnet!

9

It's not on Ethereum Mainnet, it is on the Moonbase Alpha testnet here: