Fatal error: Uncaught Error: Call to undefined function custom_project_error_log() in /home/server754566/ftp/magicznyprezent/wp-content/mu-plugins/pay-by-voucher.php:19 Stack trace: #0 /home/server754566/ftp/magicznyprezent/wp-includes/class-wp-hook.php(324): apply_voucher_discount(Object(WC_Cart)) #1 /home/server754566/ftp/magicznyprezent/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters('', Array) #2 /home/server754566/ftp/magicznyprezent/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #3 /home/server754566/ftp/magicznyprezent/wp-content/plugins/woocommerce/includes/class-wc-cart.php(1406): do_action('woocommerce_bef...', Object(WC_Cart)) #4 /home/server754566/ftp/magicznyprezent/wp-includes/class-wp-hook.php(322): WC_Cart->calculate_totals() #5 /home/server754566/ftp/magicznyprezent/wp-includes/class-wp-hook.php(348): WP_Hook->apply_filters(NULL, Array) #6 /home/server754566/ftp/magicznyprezent/wp-includes/plugin.php(517): WP_Hook->do_action(Array) #7 /home/server754566/ftp/magicznyprezent/wp-content/pl in /home/server754566/ftp/magicznyprezent/wp-content/mu-plugins/pay-by-voucher.php on line 19