Checkout Without Payment

Recently Craft provide checkout without payment but not working for me. I followed the instruction of craft doc. set config variable: allowCheckoutWithoutPayment

https://craftcms.com/docs/commerce/3.x/making-payments.html#deferred-payment-at-checkout

Here is my code.

<form autocomplete="off" novalidate method="post" class="form" id="paymentForm">
            <div class="hidden" style="display: none;">
                {{ csrfInput() }}
                {{ hiddenInput('action', 'commerce/cart/complete') }}
                {{ redirectInput('/store/order-placed/{number}') }}
            </div>

            <div class="mt-2 flex items-center justify-between">
                <div class="show-inline">
                    <button type="submit" name="submit" class="btn btn-sm btn-indigo">Submit Your Quote</button>
                    <img src="{{ siteUrl }}assets/images/ajax-loader.gif" class="ajax-loader">
                </div>
            </div>
        </form>

Thanks for help cheers