error 404 by adding a 2nd same item to cart

Hey there!

Could you please share a copy of your site’s System Status? You can find it via WooCommerce > Status.
Select “Get system report” and then “Copy for support”.? Once you’ve done that, paste it here in your response.

Hi, thanks. Here it is the system report:

### WordPress Environment ###

WordPress address (URL): https://theplan.thesouthofspain.com
Site address (URL): https://theplan.thesouthofspain.com
WC Version: 4.2.2
REST API Version: ? 1.0.8
WC Blocks Version: ? 2.5.16
Action Scheduler Version: ? 3.1.6
WC Admin Version: ? 1.2.4
Log Directory Writable: ?
WP Version: ? 5.4.2 - There is a newer version of WordPress available (5.5)
WP Multisite: –
WP Memory Limit: 512 MB
WP Debug Mode: –
WP Cron: ?
Language: en_US
External object cache: –

### Server Environment ###

Server Info: LiteSpeed
PHP Version: 7.4.9
PHP Post Max Size: 128 MB
PHP Time Limit: 30
PHP Max Input Vars: 10000
cURL Version: 7.62.0
OpenSSL/1.0.2k

SUHOSIN Installed: –
MySQL Version: 5.5.5-10.3.24-MariaDB
Max Upload Size: 128 MB
Default Timezone is UTC: ?
fsockopen/cURL: ?
SoapClient: ?
DOMDocument: ?
GZip: ?
Multibyte String: ?
Remote Post: ?
Remote Get: ?

### Database ###

WC Database Version: 4.2.2
WC Database Prefix: wp_
Total Database Size: 93.08MB
Database Data Size: 89.49MB
Database Index Size: 3.59MB
wp_woocommerce_sessions: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_woocommerce_api_keys: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_woocommerce_attribute_taxonomies: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_woocommerce_downloadable_product_permissions: Data: 0.02MB + Index: 0.06MB + Engine InnoDB
wp_woocommerce_order_items: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_woocommerce_order_itemmeta: Data: 0.08MB + Index: 0.09MB + Engine InnoDB
wp_woocommerce_tax_rates: Data: 0.02MB + Index: 0.06MB + Engine InnoDB
wp_woocommerce_tax_rate_locations: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_woocommerce_shipping_zones: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_woocommerce_shipping_zone_locations: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_woocommerce_shipping_zone_methods: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_woocommerce_payment_tokens: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_woocommerce_payment_tokenmeta: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_woocommerce_log: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_actionscheduler_actions: Data: 0.02MB + Index: 0.11MB + Engine InnoDB
wp_actionscheduler_claims: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_actionscheduler_groups: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_actionscheduler_logs: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_commentmeta: Data: 0.01MB + Index: 0.02MB + Engine MyISAM
wp_comments: Data: 0.04MB + Index: 0.03MB + Engine MyISAM
wp_h5p_contents: Data: 4.52MB + Index: 0.00MB + Engine InnoDB
wp_h5p_contents_libraries: Data: 0.17MB + Index: 0.00MB + Engine InnoDB
wp_h5p_contents_tags: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_h5p_contents_user_data: Data: 0.05MB + Index: 0.00MB + Engine InnoDB
wp_h5p_counters: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_h5p_events: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_h5p_libraries: Data: 0.47MB + Index: 0.03MB + Engine InnoDB
wp_h5p_libraries_cachedassets: Data: 0.05MB + Index: 0.00MB + Engine InnoDB
wp_h5p_libraries_hub_cache: Data: 0.09MB + Index: 0.02MB + Engine InnoDB
wp_h5p_libraries_languages: Data: 8.52MB + Index: 0.00MB + Engine InnoDB
wp_h5p_libraries_libraries: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_h5p_results: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_h5p_tags: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_h5p_tmpfiles: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_itsec_distributed_storage: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_itsec_fingerprints: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_itsec_geolocation_cache: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_itsec_lockouts: Data: 0.02MB + Index: 0.08MB + Engine InnoDB
wp_itsec_logs: Data: 0.36MB + Index: 0.11MB + Engine InnoDB
wp_itsec_mutexes: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_itsec_opaque_tokens: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_itsec_temp: Data: 0.05MB + Index: 0.06MB + Engine InnoDB
wp_itsec_user_groups: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_learndash_pro_quiz_category: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_learndash_pro_quiz_form: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_learndash_pro_quiz_lock: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_learndash_pro_quiz_master: Data: 0.05MB + Index: 0.00MB + Engine InnoDB
wp_learndash_pro_quiz_prerequisite: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_learndash_pro_quiz_question: Data: 2.52MB + Index: 0.03MB + Engine InnoDB
wp_learndash_pro_quiz_statistic: Data: 0.11MB + Index: 0.00MB + Engine InnoDB
wp_learndash_pro_quiz_statistic_ref: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_learndash_pro_quiz_template: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_learndash_pro_quiz_toplist: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_learndash_user_activity: Data: 0.02MB + Index: 0.13MB + Engine InnoDB
wp_learndash_user_activity_meta: Data: 0.08MB + Index: 0.09MB + Engine InnoDB
wp_links: Data: 0.00MB + Index: 0.00MB + Engine MyISAM
wp_litespeed_img_optm: Data: 0.02MB + Index: 0.09MB + Engine InnoDB
wp_litespeed_img_optming: Data: 0.02MB + Index: 0.05MB + Engine InnoDB
wp_litespeed_optimizer: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_ms_snippets: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_options: Data: 4.65MB + Index: 0.09MB + Engine MyISAM
wp_postmeta: Data: 58.74MB + Index: 1.16MB + Engine MyISAM
wp_posts: Data: 7.64MB + Index: 0.24MB + Engine MyISAM
wp_snippets: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_termmeta: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_terms: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_term_relationships: Data: 0.01MB + Index: 0.01MB + Engine MyISAM
wp_term_taxonomy: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_usermeta: Data: 0.06MB + Index: 0.04MB + Engine MyISAM
wp_users: Data: 0.00MB + Index: 0.01MB + Engine MyISAM
wp_wc_admin_notes: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_wc_admin_note_actions: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_wc_category_lookup: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_wc_customer_lookup: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_wc_download_log: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_wc_order_coupon_lookup: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_wc_order_product_lookup: Data: 0.02MB + Index: 0.06MB + Engine InnoDB
wp_wc_order_stats: Data: 0.02MB + Index: 0.05MB + Engine InnoDB
wp_wc_order_tax_lookup: Data: 0.02MB + Index: 0.03MB + Engine InnoDB
wp_wc_product_meta_lookup: Data: 0.02MB + Index: 0.09MB + Engine InnoDB
wp_wc_tax_rate_classes: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_wc_webhooks: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_wpforms_tasks_meta: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_yith_ywrac_email_log: Data: 0.02MB + Index: 0.00MB + Engine InnoDB
wp_yoast_seo_links: Data: 0.02MB + Index: 0.02MB + Engine InnoDB
wp_yoast_seo_meta: Data: 0.02MB + Index: 0.00MB + Engine InnoDB

### Post Type Counts ###

attachment: 536
cartflows_flow: 2
cartflows_step: 4
course: 3
custom_css: 4
customize_changeset: 6
elementor_library: 71
elementor-hf: 1
groups: 1
lesson: 25
nav_menu_item: 7
oembed_cache: 3
page: 19
post: 2
product: 3
question: 38
quiz: 24
revision: 1098
sfwd-certificates: 1
sfwd-courses: 3
sfwd-lessons: 18
sfwd-question: 647
sfwd-quiz: 26
sfwd-topic: 105
sfwd-transactions: 2
shop_order: 48
shop_order_refund: 8
wc_membership_plan: 2
wc_user_membership: 3
wp_block: 1
wpforms: 1
ywrac_cart: 2
ywrac_email: 1

### Security ###

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

### Active Plugins (29) ###

Autocomplete WooCommerce Orders: by Liam McArthur – 1.3.1 – Installed version not tested with active version of WooCommerce 4.2.2
Autoptimize: by Frank Goossens (futtta) – 2.7.6
iThemes Security: by iThemes – 7.8.0
Code Snippets: by Code Snippets Pro – 2.14.0
Cookie Notice: by dFactory – 1.3.2
Elementor Pro: by Elementor.com – 2.10.3
Elementor: by Elementor.com – 2.9.14
GP Premium: by Tom Usborne – 1.11.3
H5P: by Joubel – 1.15.0
H5P Mods: by H5P – 0.0.1
LearnDash LMS - Course Grid: by LearnDash – 1.6.0
LearnDash LMS - WooCommerce Integration: by LearnDash – 1.8.0 – Installed version not tested with active version of WooCommerce 4.2.2
Menu Icons: by ThemeIsle – 0.12.5
MP3-jPlayer: by Simon Ward – 2.7.3
PixelYourSite: by PixelYourSite – 7.1.11
Really Simple SSL: by Really Simple Plugins – 3.3.4
LearnDash LMS: by LearnDash – 3.2.2
Uncanny Toolkit for LearnDash: by Uncanny Owl – 3.3.3
Unlist Posts & Pages: by Nikhil Chavan – 1.0.4
Checkout Field Editor for WooCommerce: by ThemeHigh – 1.4.3
WooCommerce Email Customizer: by cxThemes – 3.33 – Installed version not tested with active version of WooCommerce 4.2.2
EU VAT Compliance for WooCommerce (Free): by David Anderson – 1.14.10
WooCommerce Stripe Gateway: by WooCommerce – 4.5.2
WooCommerce Services: by Automattic – 1.24.1
WooCommerce: by Automattic – 4.2.2 (update to version 4.4.1 is available)
WPS Hide Login: by WPServeur
NicolasKulka
tabrisrp – 1.5.6

YITH Custom ThankYou Page for Woocommerce Premium: by YITH – 1.1.9 – Installed version not tested with active version of WooCommerce 4.2.2
YITH WooCommerce Customize My Account Page: by YITH – 2.5.15 – Installed version not tested with active version of WooCommerce 4.2.2
YITH WooCommerce PDF Invoice and Shipping List Premium: by YITH – 2.0.11 – Installed version not tested with active version of WooCommerce 4.2.2

### Inactive Plugins (9) ###

Colorlib Login Customizer: by Colorlib – 1.2.96
LearnDash Content Cloner: by WisdmLabs – 1.2.9.1
LearnDash LMS - Elementor: by LearnDash – 1.0.1
LearnDash LMS - Stripe Integration: by LearnDash – 1.6.0
Loco Translate: by Tim Whitlock – 2.4.2
Nav Menu Roles: by Kathy Darling – 1.10.2
Nav Menu Roles + WooCommerce Memberships Bridge: by Kathy Darling – 1.0.0 – Installed version not tested with active version of WooCommerce 4.2.2
WP Fastest Cache: by Emre Vona – 0.9.0.9
YITH WooCommerce Recover Abandoned Cart Premium: by YITH – 1.4.0 – Installed version not tested with active version of WooCommerce 4.2.2

### Must Use Plugins (3) ###

Elementor Safe Mode: by Elementor.com – 1.0.0
installatron_hide_status_test.php: by  –
LearnDash LMS Multisite: by LearnDash – 1.0.0

### Settings ###

API Enabled: –
Force SSL: –
Currency: GBP (￡)
Currency Position: right
Thousand Separator: .
Decimal Separator: ,
Number of Decimals: 2
Taxonomies: Product Types: course (course)
external (external)
grouped (grouped)
simple (simple)
subscription (subscription)
variable (variable)
variable subscription (variable-subscription)

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 ###

Shop base: #7894 - /shop/
Cart: #7895 - /cart/
Checkout: ? Page does not contain the shortcode.
My account: #7897 - /my-account/
Terms and conditions: #26183 - /terms-and-conditions/

### Theme ###

Name: GeneratePress Child
Version: 0.1
Author URL: https://tomusborne.com
Child Theme: ?
Parent Theme Name: GeneratePress
Parent Theme Version: 2.4.2
Parent Theme Author URL: https://tomusborne.com
WooCommerce Support: ?

### Templates ###

Overrides: /home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/admin-cancelled-order.php version 3.7.0 is out of date. The core version is 4.1.0
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/admin-failed-order.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/admin-new-order.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/customer-completed-order.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/customer-invoice.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/customer-new-account.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/customer-note.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/customer-on-hold-order.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/customer-processing-order.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/customer-refunded-order.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/customer-reset-password.php version 3.7.0 is out of date. The core version is 4.0.0
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/email-addresses.php version 3.5.4 is out of date. The core version is 3.9.0
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/email-customer-details.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/email-downloads.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/email-footer.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/email-header.php version 2.4.0 is out of date. The core version is 4.0.0
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/email-order-details.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/email-order-items.php
/home/spanis16/theplan.thesouthofspain.com/wp-content/plugins/woocommerce-email-control/templates/emails/woocommerce/email-styles.php version 3.3.0 is out of date. The core version is 4.0.0

Outdated Templates: ?
					
					
						Learn how to update

### Action Scheduler ###

Complete: 41
Oldest: 2020-07-21 02:43:08 +0000
Newest: 2020-08-20 10:45:09 +0000

Thanks for that! This kind of problem is usually caused by either a conflict with your theme or with another plugin.
?
The best way to determine this is to:

• Temporarily switch your theme to Storefront
• Disable all plugins except for WooCommerce
• Repeat the action that is causing the problem

If you’re not seeing the same problem after completing the conflict test, then you know the problem was with the plugins and/or theme you deactivated. To figure out which plugin is causing the problem, reactivate your other plugins one by one, testing after each, until you find the one causing conflict. You can find a more detailed explanation on how to do a conflict test here.

Hey there, since I haven’t heard back from you in awhile I’ll mark this thread as resolved now. If you have any further questions, I recommend creating a new thread.