I need help to verify and publish my smart contract on binance smart chain

Hello, I need help to verify and publish my smart contract on BSC. It always throw me an error that says: " Error! Unable to generate Contract ByteCode and ABI (General Exception, unable to get compiled [bytecode]) " below is the screen shot. I tried to revised it but it sometimes throw me a constructor error again.

Here is the code of my constructor:

// SPDX-License-Identifier: MIT

import "@openzeppelin/contracts/token/ERC20/ERC20.sol";

pragma solidity ^0.8.0;

contract casinoDapp {
    //global dynamic array for playerlist.
    uint public nowPlaying;
    uint public maxPlayer;
    uint public minBet;
    uint public currentBet;
    uint public totalPayin;
    uint public totalPayout;
    uint public totalRefund;
    uint public managementFee;
    address payable public manager;
    address payable[] private playerList;
    address payable[] private refundedPlayers;
    address payable[] private winnerList; 
    uint []private payinList;
    uint []private payoutList;
    uint []private refundList;
    event ownershipTransferred(address indexed manager, address indexed newManager);
    constructor() {
    //msg.sender is a global variable used to store contract address to manager.
    manager = payable(msg.sender); 
    maxPlayer =2; 
    minBet = 0.01 ether; //default is 0.01 ether.
    managementFee = 1; //fixed fees.
    totalPayin = getCasinoVolume();
    totalPayout = getTotalPayout();
    totalRefund = getTotalRefund();
    emit ownershipTransferred(address(0), msg.sender);

To verify it you can have to flatten the code. There is a plugin on Remix IDE.

have tried flatten the code and this is what I got as error below on the file photo.

The bytecode and Abi that Bscscan is looking for isn't exactly the same as what they've got on my code.

My contract ABI code is different from bscscan is looking for. Need help to fix it?

Hi, please have a look at this tutorial:

And for the next time, please search at the forum at first.

after flattening copy paste the first line - // SPDX-License-Identifier: MIT