swapExactTokensForETHSupportingFeeOnTransferTokens fails when from == uniswapPair address

Smart Contracts
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#1

I want to apply a fee of the 10% every time my token is transferred (except the case the from is the owner).
When i use PancakeSwap I'm able to create a pool, however, when I try to swap the token from the just created pool, I receive the error 'Pancake: TRANSFER_FAILED'

This happen when the from filed is equal to the _uniswapV2Pair address.

Why this happens and how to fix this problem?

The relevant token code is below:

// to avoid cycles
modifier lockSwapTokenForETH {
    _inSwapTokenForETH = true;
    _;
    _inSwapTokenForETH = false;

} 

function _transfer(address from, address to, uint256 amount) private {
     // by adding "from != _uniswapV2Pair" it works!
    if (!_inSwapTokenForETH && from != _owner){           
        uint feeAmount = amount * 10 / 100;

        _transfer(from, address(this), feeAmount);
        _swapTokensForEth(feeAmount);   

        _transfer(from, to, amount - feeAmount);
        emit Transfer(from, to, amount - feeAmount);
    }
    else{
        _transfer(from, to, amount);
        emit Transfer(from, to, amount);
    }
}

function _swapTokensForEth(uint256 tokenAmount) private lockSwapTokenForETH {
    address[] memory path = new address[](2);
    path[0] = address(this);
    path[1] = _uniswapV2Router.WETH();

    _approve(address(this), address(_uniswapV2Router), tokenAmount);

    _uniswapV2Router.swapExactTokensForETHSupportingFeeOnTransferTokens(tokenAmount, 0, path, address(this), block.timestamp);
}

receive() external payable {}