Error in plugin @nomiclabs/hardhat-etherscan: The contract verification failed. Reason: Fail - Unable to verify - with arguments

I am trying to verify my contract with arguments and I am getting this error:

Error in plugin @nomiclabs/hardhat-etherscan: The contract verification failed.
Reason: Fail - Unable to verify

I am also importing Open Zeppelin contracts ERC721Enumerable and Ownable.

Here's my NFTCollectible.sol

pragma solidity 0.8.10;

import "@openzeppelin/contracts/token/ERC721/extensions/ERC721Enumerable.sol";
import "@openzeppelin/contracts/access/Ownable.sol";
import "hardhat/console.sol";

contract NFTCollectible is ERC721Enumerable, Ownable {
    using Strings for uint256;

    string public baseURI;
    string public baseExtension = ".json";
    uint256 public cost = 0.08 ether;
    uint256 public maxSupply = 5000;
    uint256 public maxMintAmount = 25;
    mapping(address => uint256) public addressMintedBalance;

    constructor(
        string memory _name,
        string memory _symbol,
        string memory _initBaseURI,
        string memory _initNotRevealedUri
    ) ERC721(_name, _symbol) {
        setBaseURI(_initBaseURI);
        setNotRevealedURI(_initNotRevealedUri);
    }

    function _baseURI() internal view virtual override returns (string memory) {
        return baseURI;
    }

    function mint(uint256 _mintAmount) public payable {
        require(!paused, "the contract is paused");
        uint256 supply = totalSupply();
        require(_mintAmount > 0, "need to mint at least 1 NFT");
    }

    function walletOfOwner(address _owner)
        public
        view
        returns (uint256[] memory)
    {
        uint256 ownerTokenCount = balanceOf(_owner);
        uint256[] memory tokenIds = new uint256[](ownerTokenCount);
        for (uint256 i; i < ownerTokenCount; i++) {
            tokenIds[i] = tokenOfOwnerByIndex(_owner, i);
        }
        return tokenIds;
    }

    function tokenURI(uint256 tokenId)
        public
        view
        virtual
        override
        returns (string memory)
    {
        require(
            _exists(tokenId),
            "ERC721Metadata: URI query for nonexistent token"
        );

        string memory currentBaseURI = _baseURI();
        return
            bytes(currentBaseURI).length > 0
                ? string(
                    abi.encodePacked(
                        currentBaseURI,
                        tokenId.toString(),
                        baseExtension
                    )
                )
                : "";
    }

    function setCost(uint256 _newCost) public onlyOwner {
        cost = _newCost;
    }

    function setBaseURI(string memory _newBaseURI) public onlyOwner {
        baseURI = _newBaseURI;
    }

    function setBaseExtension(string memory _newBaseExtension)
        public
        onlyOwner
    {
        baseExtension = _newBaseExtension;
    }

    function withdraw() public payable onlyOwner {
        (bool me, ) = payable(owner())
            .call{value: address(this).balance}("");
        require(me);
    }
}

Here's my deploy.js

const main = async () => {
  const nftContractFactory = await hre.ethers.getContractFactory('NFTCollectible');
  const nftContract = await nftContractFactory.deploy(
      "NFTCollectible",
      "NFTC",
      "ipfs://CID",
      "https://www.example.com"
  );
  await nftContract.deployed();
  console.log("Contract deployed to:", nftContract.address);
};

const runMain = async () => {
  try {
    await main();
    process.exit(0);
  } catch (error) {
    console.log(error);
    process.exit(1);
  }
};

runMain();

Here's my hardhat.config

require('@nomiclabs/hardhat-waffle');
require('@nomiclabs/hardhat-etherscan');
require('dotenv').config();

module.exports = {
  solidity: '0.8.10',
  networks: {
    rinkeby: {
      url: process.env.STAGING_ALCHEMY_KEY,
      accounts: [process.env.PRIVATE_KEY],
    },
    mainnet: {
      chainId: 1,
      url: process.env.PROD_ALCHEMY_KEY,
      accounts: [process.env.PRIVATE_KEY],
      gasPrice: 3000000
    },
  },
  etherscan: {
    apiKey: process.env.ETHERSCAN_KEY
  }
};

I realize Hardhat does not support 0.8.10+ compiler version, but no other versions work either. Same error.