Cash on Delivery not visible in the checkout

When Cash on Delivery option has to be enabled for shipping methods, in the result cash on delivery is not available in the shop’s checkout.

Status report

### WordPress Environment ###

Home URL: https://127.0.0.1/wordpress
Site URL: https://127.0.0.1/wordpress
WC Version: 3.1.0
Log Directory Writable: ?
WP Version: 4.8
WP Multisite: –
WP Memory Limit: ? 40 MB - We recommend setting memory to at least 64MB. See: Increasing memory allocated to PHP
WP Debug Mode: –
WP Cron: ?
Language: en_US

### Server Environment ###

Server Info: Apache
PHP Version: 7.0.18
PHP Post Max Size: 40 MB
PHP Time Limit: 120
PHP Max Input Vars: 1000
cURL Version: 7.51.0
OpenSSL/1.0.2h

SUHOSIN Installed: –
MySQL Version: 5.7.18
Max Upload Size: 40 MB
Default Timezone is UTC: ?
fsockopen/cURL: ?
SoapClient: ? Your server does not have the SoapClient class enabled - some gateway plugins which use SOAP may not work as expected.
DOMDocument: ?
GZip: ?
Multibyte String: ?
Remote Post: ?
Remote Get: ?

### Database ###

WC Database Version: 3.1.0
WC Database Prefix: wp_
woocommerce_sessions: ?
woocommerce_api_keys: ?
woocommerce_attribute_taxonomies: ?
woocommerce_downloadable_product_permissions: ?
woocommerce_order_items: ?
woocommerce_order_itemmeta: ?
woocommerce_tax_rates: ?
woocommerce_tax_rate_locations: ?
woocommerce_shipping_zones: ?
woocommerce_shipping_zone_locations: ?
woocommerce_shipping_zone_methods: ?
woocommerce_payment_tokens: ?
woocommerce_payment_tokenmeta: ?
MaxMind GeoIP Database: ? The MaxMind GeoIP Database does not exist - Geolocation will not function. You can download and install it manually from https://dev.maxmind.com/geoip/legacy/geolite/ to the path: . Scroll down to "Downloads" and download the "Binary / gzip" file next to "GeoLite Country". Please remember to uncompress GeoIP.dat.gz and upload the GeoIP.dat file only.

### Security ###

Secure connection (HTTPS): ?Your store is not using HTTPS. Learn more about HTTPS and SSL Certificates.
Hide errors from visitors: ?

### Active Plugins (8) ###

All In One SEO Pack: by Michael Torbert – 2.3.13.2
Homepage Control: by WooThemes – 2.0.2
oik weight zone shipping: by bobbingwide – 0.1.1
Title Toggle for Storefront Theme: by Wooassist – 1.2.3
Widget Logic: by wpchefgadget
alanft – 5.8.2

WooCommerce COD Advanced: by AheadZen – 1.3.0
WooCommerce: by Automattic – 3.1.0
WP-Mail-SMTP: by Callum Macdonald – 0.10.1

### Settings ###

API Enabled: ?
Force SSL: –
Currency: PLN (z?)
Currency Position: right
Thousand Separator: 
Decimal Separator: ,
Number of Decimals: 2
Taxonomies: Product Types: external (external)
grouped (grouped)
simple (simple)
variable (variable)

Taxonomies: Product Visibility: exclude-from-catalog (exclude-from-catalog)
exclude-from-search (exclude-from-search)
featured (featured)
outofstock (outofstock)
rated-1 (rated-1)
rated-2 (rated-2)
rated-3 (rated-3)
rated-4 (rated-4)
rated-5 (rated-5)

### WC Pages ###

Shop base: #5 - /shop/
Cart: #6 - /koszyk/
Checkout: #7 - /checkout/
My account: #8 - /my-account/

### Theme ###

Name: Storefront
Version: 2.2.4
Author URL: https://woocommerce.com/
Child Theme: ? – If you are modifying WooCommerce on a parent theme that you did not build personally we recommend using a child theme. See: How to create a child theme
WooCommerce Support: ?

### Templates ###

Overrides: –

I have enabled the plugin and cash on delivery gateway at wp-admin. This option is not working with plugin oik weight zone shipping. When cod has to be enabled for weight zone shipping delivery only, the issue appears. The issue does not appear when cash on delivery is enabled for every delivery method.