Gas estimation failed

I added mint function to safemoon but when I mint, I get error.

:1234: Code to reproduce

This is my code.

 function _mint(address account, uint256 amount) internal {
        require(account != address(0), "BEP20: mint to the zero address");
        uint256 currentRate = _getRate();
        uint256 rAmount = amount.mul(currentRate);
        _rOwned[account] = _rOwned[account].add(rAmount);
        _tTotal = _tTotal.add(amount);
        _rTotal = _rTotal.add(rAmount);
        emit Transfer(address(0), account, amount);

plz give me advice.

:computer: Environment

Remix IDE

nobody can help me? :frowning: