Fatal error

Hello,
For several days we have a problem that appears on the order page. It is not possible to finalize the order. I found this critical error in logs:

WPDesk_Flexible_Shipping_SaaS_Maintenance_Mode_Exception in /wp-content/plugins/flexible-shipping/vendor/wpdesk/wp-wpdesk-connect/src/saas/class-saas-shipping-service.php:676
Stack trace:
#0 /wp-content/plugins/flexible-shipping/vendor/wpdesk/wp-wpdesk-connect/src/saas/checkout-fields/class-saas-checkout-fields-checkout.php(157): WPDesk_Flexible_Shipping_SaaS_Shipping_Service->get_fields_for_targets(Array)
#1 /wp-includes/class-wp-hook.php(286): WPDesk_Flexible_Shipping_SaaS_Shipping_Checkout_Fields_Checkout->maybe_display_fields_on_checkout_page('')
#2 /wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters('', Array)
#3 /wp-includes/plugin.php(465): WP_Hook->do_action(Array)
#4 /wp-content/plugins/woocommerce/templates/checkout/review-order.php(75): do_action('woocommerce_rev...')
#5 /wp-content/plugins/woocommerce/ w /home/podgorny/ftp/iqnails/wp-content/plugins/flexible-shipping/vendor/wpdesk/wp-wpdesk-connect/src/saas/class-saas-shipping-service.php w linii 676

Nothing was changed or updated before this problem occurred suddenly.
After that I actualized all the plugins and motive, but problem is still active. I had to swich off this plugin.
I kindly ask you for help with this problem.

I attached system raport.

### WordPress Environment ###

WordPress address (URL): https://www.iqnails.pl
Site address (URL): https://www.iqnails.pl
WC Version: 3.7.0
REST API Version: ? 1.0.2
Log Directory Writable: ?
WP Version: 5.2.2
WP Multisite: –
WP Memory Limit: 1 GB
WP Debug Mode: –
WP Cron: ?
Language: pl_PL
External object cache: –

### Server Environment ###

Server Info: Apache/2
PHP Version: 7.0.33 - Rekomendujemy u?ywanie PHP w wersji 7.2 lub wy?szej w celu osi?gni?cia wi?kszej wydajno?ci oraz bezpieczeństwa. Jak zaktualizowa? wersj? PHP
PHP Post Max Size: 64 MB
PHP Time Limit: 120
PHP Max Input Vars: 1000
cURL Version: 7.47.0
GnuTLS/3.4.10

SUHOSIN Installed: –
MySQL Version: 5.5.5-10.1.41-MariaDB
Max Upload Size: 64 MB
Default Timezone is UTC: ?
fsockopen/cURL: ?
SoapClient: ?
DOMDocument: ?
GZip: ?
Multibyte String: ?
Remote Post: ?
Remote Get: ?

### Database ###

WC Database Version: 3.7.0
WC Database Prefix: iq17n_
MaxMind GeoIP Database: ?
Ca?kowity rozmiar bazy danych: 39.11MB
Rozmiar bazy danych: 33.66MB
Rozmiar indeksu bazy danych: 5.45MB
iq17n_woocommerce_sessions: Data: 0.38MB + Index: 0.02MB + Engine InnoDB
iq17n_woocommerce_api_keys: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
iq17n_woocommerce_attribute_taxonomies: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
iq17n_woocommerce_downloadable_product_permissions: Data: 0.02MB + Index: 0.06MB + Engine InnoDB
iq17n_woocommerce_order_items: Data: 0.06MB + Index: 0.02MB + Engine InnoDB
iq17n_woocommerce_order_itemmeta: Data: 0.38MB + Index: 0.20MB + Engine InnoDB
iq17n_woocommerce_tax_rates: Data: 0.02MB + Index: 0.06MB + Engine InnoDB
iq17n_woocommerce_tax_rate_locations: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
iq17n_woocommerce_shipping_zones: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
iq17n_woocommerce_shipping_zone_locations: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
iq17n_woocommerce_shipping_zone_methods: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
iq17n_woocommerce_payment_tokens: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
iq17n_woocommerce_payment_tokenmeta: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
iq17n_woocommerce_log: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
cerber_acl: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
cerber_blocks: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
cerber_countries: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
cerber_lab: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
cerber_lab_ip: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
cerber_lab_net: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
cerber_log: Data: 0.39MB + Index: 0.30MB + Engine InnoDB
cerber_qmem: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
cerber_traffic: Data: 1.52MB + Index: 0.11MB + Engine InnoDB
iq17n_accordeonmenuck_styles: Data: 0.05MB + Index: 0.00MB + Engine InnoDB
iq17n_cerber_files: Data: 9.56MB + Index: 0.00MB + Engine InnoDB
iq17n_cerber_sets: Data: 0.08MB + Index: 0.00MB + Engine InnoDB
iq17n_cerber_uss: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
iq17n_commentmeta: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
iq17n_comments: Data: 0.14MB + Index: 0.09MB + Engine InnoDB
iq17n_dotpay_instructions: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
iq17n_dotpay_oneclick_cards: Data: 0.02MB + Index: 0.06MB + Engine InnoDB
iq17n_hook_list: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
iq17n_iq17n_iq17n_iq17n_iq17n_iq17n_hook_list: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
iq17n_links: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
iq17n_options: Data: 2.50MB + Index: 0.13MB + Engine InnoDB
iq17n_postmeta: Data: 13.52MB + Index: 3.03MB + Engine InnoDB
iq17n_posts: Data: 3.52MB + Index: 0.38MB + Engine InnoDB
iq17n_smush_dir_images: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
iq17n_termmeta: Data: 0.05MB + Index: 0.03MB + Engine InnoDB
iq17n_terms: Data: 0.06MB + Index: 0.03MB + Engine InnoDB
iq17n_term_relationships: Data: 0.22MB + Index: 0.13MB + Engine InnoDB
iq17n_term_taxonomy: Data: 0.08MB + Index: 0.06MB + Engine InnoDB
iq17n_usermeta: Data: 0.19MB + Index: 0.17MB + Engine InnoDB
iq17n_users: Data: 0.02MB + Index: 0.05MB + Engine InnoDB
iq17n_wc_download_log: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
iq17n_wc_product_meta_lookup: Data: 0.09MB + Index: 0.09MB + Engine InnoDB
iq17n_wc_tax_rate_classes: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
iq17n_wc_webhooks: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
iq17n_wpmm_subscribers: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
iq17n_yoast_seo_links: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
iq17n_yoast_seo_meta: Data: 0.17MB + Index: 0.00MB + Engine InnoDB
zzz_RtnetExportedOrders: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
zzz_RtnetSubsyncSecret: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
zzz_RtnetTasks: Data: 0.02MB + Index: 0.00MB + Engine InnoDB

### Security ###

Secure connection (HTTPS): ?
Hide errors from visitors: ?

### Active Plugins (23) ###

Polylang: przez WP SYNTEX – 2.6.3
RTNET SubSync: przez rtnet.pl – 1.1 – Nietestowane z u?ywan? wersj? WooCommerce
BackWPup: przez Inpsyde GmbH – 3.6.10
Klasyczny edytor: przez Kontrybutorzy WordPressa – 1.5
Divi 100 Login Page: przez Elegant Themes – 0.0.1
Duplicate Page: przez mndpsingh287 – 3.9
Nextend Accordion Menu: przez Nextend – 9.3.9
Orbisius Child Theme Creator: przez Svetoslav Marinov (Slavi) – 1.5.0
GDPR Cookie Consent Banner: przez termly – 2.3.14
WC Product Builder For Divi: przez AbdElfatah AboElgit – 1.4.4 – Nietestowane z u?ywan? wersj? WooCommerce
Multi Currency for WooCommerce: przez VillaTheme – 2.1.3.5 – Nietestowane z u?ywan? wersj? WooCommerce
Hyyan WooCommerce Polylang Integration: przez Hyyan Abo Fakher – 1.4.3 – Nietestowane z u?ywan? wersj? WooCommerce
WooCommerce Dotpay Gateway: przez Dotpay ([email protected]) – 3.2.4 – Nietestowane z u?ywan? wersj? WooCommerce
Booster for WooCommerce: przez Algoritmika Ltd – 4.4.1 – Nietestowane z u?ywan? wersj? WooCommerce
WooCommerce InPost: przez WP Desk – 3.6.4 – Nietestowane z u?ywan? wersj? WooCommerce
WooCommerce Sequential Order Numbers: przez SkyVerge – 1.9.0
WooCommerce: przez Automattic – 3.7.0
Yoast SEO: przez Zespó? Yoast – 11.9
WP Cerber Security, Antispam & Malware Scan: przez Cerber Tech Inc. – 8.4
WP Tryb Konserwacji: przez Designmodo – 2.2.4
WP Rollback: przez Impress.org – 1.6
Smush: przez WPMU DEV – 3.2.4
WP Desk Helper: przez WP Desk – 1.7.0 – Nietestowane z u?ywan? wersj? WooCommerce

### Inactive Plugins (4) ###

Autoptimize: przez Frank Goossens (futtta) – 2.5.1
Flexible Shipping: przez WP Desk – 3.6.4
WooCommerce Active Payments: przez WP Desk – 3.1.1 – Nietestowane z u?ywan? wersj? WooCommerce
WooCommerce eNadawca Poczta Polska: przez WP Desk – 1.5.14 – Nietestowane z u?ywan? wersj? WooCommerce

### Must Use Plugins (1) ###

ET Support Center :: Must-Use Plugins Autoloader: przez Elegant Themes –

### Settings ###

API Enabled: ?
Force SSL: ?
Currency: PLN (z?)
Currency Position: right_space
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)

Connected to WooCommerce.com: –

### WC Pages ###

Strona sklepu: #86 - /sklep/
Koszyk: #5 - /koszyk/
Zamówienie: #6 - /zamowienie/
Moje konto: #7 - /moje-konto/
Regulamin: #123 - /regulamin-sklepu/

### Theme ###

Name: Divi Child theme of Divi
Version: 3.0.78
Author URL: 
Child Theme: ?
Parent Theme Name: Divi
Parent Theme Version: 3.27.3
Parent Theme Author URL: https://www.elegantthemes.com
WooCommerce Support: ?

### Templates ###

Overrides: –

### Action Scheduler ###

Complete: 3
Oldest: 2019-08-23 12:00:48 +0200
Newest: 2019-08-23 12:00:48 +0200

Pending: 0
Oldest: –
Newest: –

Canceled: 0
Oldest: –
Newest: –

In-progress: 0
Oldest: –
Newest: –

Failed: 0
Oldest: –
Newest: –

Best regards
Pearon

The page I need help with: [log in to see the link]