Prevent WooCommerce Subscriptions renewal coupons

functions.php

<?php
// Made by Goran from https://wpgens.com 
add_action( 'wcs_renewal_order_created', 'remove_discount_from_renewal', 10, 2 );

function remove_discount_from_renewal( $renewal_order, $subscription ) {
    // Check if there is a specific coupon applied that you want to remove
    foreach ( $renewal_order->get_items('coupon') as $item_id => $item ) {
        if ( 'specific_coupon_code' === $item->get_code() ) {
            // Remove the coupon
            $renewal_order->remove_coupon( $item->get_code() );

            // Optionally, adjust the total if needed
            $renewal_order->calculate_totals();
        }
    }
}