Fix WordPress and WooCommerce Bugs: The Complete Troubleshooting & Optimization Guide for a Faster, Safer Online Store

If your WooCommerce store is acting up—random “critical error” messages, checkout failures, cart totals that don’t update, slow product pages, or payment gateways refusing to cooperate—take a breath. You’re not alone, and more importantly, you’re not stuck.

Most store problems come from a handful of predictable causes:

  • Plugin conflicts (the #1 usual suspect)
  • Theme overrides that break WooCommerce templates
  • Caching/CDN issues that show old cart/checkout data
  • Server limits (memory, PHP version, timeouts)
  • Database issues and background task failures (cron)
  • Outdated WooCommerce extensions or payment/shipping integrations
  • Security rules (WAF/firewall) blocking legitimate requests

Here’s the good news: once you learn a repeatable diagnostic process, you can fix WordPress and WooCommerce bugs without playing whack-a-mole.

This post gives you a practical workflow you can follow whether you’re a store owner, marketer, VA, or developer. You’ll learn how to identify the root cause, apply safe fixes, and prevent the same mess from coming back next update cycle.

Why WooCommerce Bugs Happen (and why they feel “random”)

WooCommerce isn’t one program—it’s an ecosystem. A typical store includes:

  • WordPress core
  • WooCommerce plugin
  • A theme (often with WooCommerce-specific template overrides)
  • 10–40+ plugins (SEO, cache, security, page builder, email, analytics)
  • Payment gateway plugins
  • Shipping/tax plugins
  • A hosting stack (PHP, MySQL/MariaDB, server caching, CDN)

When something updates—WordPress, WooCommerce, a theme, a gateway plugin—compatibility can wobble. And because issues often show up only during certain actions (add to cart, apply coupon, checkout, refund, subscription renewal), it can feel random.

But it’s usually not random. There’s almost always a log, a conflict, or a misconfiguration behind it.

The Golden Rule: Fix Bugs Without Breaking Your Live Store

Before we jump into fixes, let’s set the tone: don’t troubleshoot on production without a safety net.

Do this first (seriously)

  1. Backup your site (files + database).

    • Use your host backups, or plugins like UpdraftPlus / BlogVault.

  2. Create a staging site (one-click staging if your host provides it).

  3. Document what changed (recent plugin/theme updates, new plugins, code snippets).

If your store is making money, treat fixes like surgery: controlled, logged, reversible.

Step-by-Step Workflow to Fix WordPress and WooCommerce Bugs

This is the exact sequence that saves hours.

Step 1: Reproduce the bug (and define the trigger)

You need a clean description like:

  • “Cart total doesn’t update after applying coupon”
  • “Checkout fails when selecting Stripe + shipping method”
  • “Product pages are slow only for logged-in users”
  • “Admin crashes when editing variable products”

Write down:

  • Where it happens (cart, checkout, admin, product page)
  • Who it happens to (guests, logged-in users, admins only)
  • What triggers it (coupon, shipping change, payment method, specific product)

Step 2: Turn on logging (the bug’s confession tape)

Enable WordPress debug (safe mode)

In wp-config.php (preferably on staging):

define('WP_DEBUG', true);
define('WP_DEBUG_LOG', true);
define('WP_DEBUG_DISPLAY', false);

This writes errors to: /wp-content/debug.log

Enable WooCommerce logs

Go to: WooCommerce → Status → Logs Then pick recent logs (especially for payment gateways like Stripe/PayPal).

Step 3: Check WooCommerce Status for obvious red flags

Go to: WooCommerce → Status Look for:

  • Outdated template overrides
  • Low memory limit
  • REST API issues
  • Cron issues
  • Missing PHP extensions
  • Database tables needing updates

Step 4: Identify if it’s theme, plugin, cache, or server

This is where you stop guessing.

  • If it breaks only with your theme → likely theme override issue
  • If it breaks after installing/updating a plugin → likely conflict
  • If cart/checkout behaves weirdly → likely caching/CDN/session issue
  • If you see timeouts/500 errors → likely server resources or PHP fatal error

The Most Common WooCommerce Bugs (and How to Fix Them)

Let’s tackle the big ones.

1) “Cart Not Updating” or “Checkout Page Looks Broken”

Symptoms

  • Add to cart doesn’t work or button spins forever
  • Cart totals don’t update
  • Shipping changes don’t reflect
  • Checkout fields disappear
  • “Something went wrong” AJAX errors

Usual causes

  • Aggressive caching on cart/checkout
  • JavaScript errors from theme/plugins
  • Minification/combine settings breaking scripts
  • CDN caching dynamic pages
  • Session/cookie issues

Fix checklist

✅ Exclude these pages from caching:

  • /cart/
  • /checkout/
  • /my-account/

✅ Disable JS minification temporarily If you use:

  • Autoptimize
  • WP Rocket
  • LiteSpeed Cache
  • SiteGround Optimizer Turn off JS combine/minify, test again.

✅ Check browser console for JS errors Open DevTools → Console and look for red errors. A single JS error can break checkout entirely.

✅ Regenerate permalinks Go to: Settings → Permalinks → Save (no changes needed). This refreshes rewrite rules.

✅ Clear all layers of cache

  • Plugin cache
  • Server cache
  • CDN cache (Cloudflare, etc.)

Helpful link: Cloudflare caching guidance https://developers.cloudflare.com/cache/

2) “Critical Error” / White Screen / 500 Error After an Update

Symptoms

  • Site or admin crashes after plugin/theme update
  • “There has been a critical error on this website”
  • Error 500 on product pages
  • Admin becomes unreachable

Usual causes

  • PHP fatal error due to incompatibility
  • Memory exhaustion
  • A function conflict (duplicate classes/functions)
  • Old theme override incompatible with latest WooCommerce

Fix checklist

✅ Read the error log

  • /wp-content/debug.log
  • Hosting error logs (cPanel / host panel)

✅ Increase PHP memory In wp-config.php:

define('WP_MEMORY_LIMIT', '256M');

✅ Disable plugins quickly (without admin) Rename the plugins folder via FTP:

  • /wp-content/plugins/ → /wp-content/plugins-disabled/

If site loads, it’s plugin conflict. Rename it back, then disable plugins one-by-one.

✅ Switch to a default theme Temporarily switch to Storefront or Twenty Twenty-Four to confirm theme issue.

WooCommerce’s official theme (great for testing): https://woocommerce.com/storefront/

3) Checkout Errors (Payments Failing, Orders Not Completing)

Symptoms

  • “Payment failed” but card is fine
  • Stripe/PayPal errors
  • Orders stuck on “Pending payment”
  • Checkout redirects endlessly
  • 403/400 errors during payment

Usual causes

  • Gateway plugin outdated
  • SSL/mixed content issues
  • Security plugin blocking REST/AJAX
  • Cloudflare/WAF blocking gateway calls
  • Webhook misconfiguration (Stripe/PayPal)
  • Currency mismatch or unsupported payment method

Fix checklist

✅ Update the payment gateway plugin first (Stripe, PayPal, Klarna, Square, etc.)

✅ Confirm SSL is clean No mixed content. Use: https://www.whynopadlock.com/

✅ Check WooCommerce → Status → Logs Look for gateway errors and messages like:

  • webhook signature mismatch
  • invalid request
  • authentication failure

✅ Fix webhooks For Stripe, confirm webhook endpoints match your domain and are active. Stripe docs (webhooks overview): https://stripe.com/docs/webhooks

✅ Whitelist WooCommerce endpoints in security/WAF Security plugins can block:

  • /wc-api/
  • /wp-json/
  • admin-ajax.php

4) Shipping or Tax Calculations Wrong

Symptoms

  • Shipping not showing
  • “No shipping options were found”
  • Tax not applied correctly
  • Rates change unexpectedly

Usual causes

  • Incorrect shipping zones
  • Caching interfering with location detection
  • Conflict with address validation plugins
  • Outdated shipping extension
  • Geolocation misconfigured

Fix checklist

✅ Verify Shipping Zones WooCommerce → Settings → Shipping → Zones Make sure:

  • zones are ordered correctly
  • each zone has methods (flat rate, free shipping, etc.)
  • postcode rules are correct

✅ Test with a clean browser Try incognito mode to avoid cached sessions.

✅ Disable geolocation temporarily WooCommerce → Settings → General → Default customer location Try “Shop base address” temporarily to confirm geolocation issue.

5) WooCommerce Emails Not Sending (Orders, Password Resets, etc.)

Symptoms

  • Customers don’t get order emails
  • Admin doesn’t get new order notifications
  • Password reset emails never arrive

Usual causes

  • WordPress wp_mail() unreliable on many hosts
  • Emails going to spam (no SMTP authentication)
  • Plugin conflict with email templates

Fix checklist

✅ Use SMTP (the real fix) Install a reliable SMTP plugin like WP Mail SMTP and connect:

  • SendGrid
  • Mailgun
  • Amazon SES
  • Gmail (less ideal for stores)

WP Mail SMTP (popular option): https://wpmailsmtp.com/

✅ Test email logs Many SMTP plugins include email logging—super helpful.

✅ Check WooCommerce email settings WooCommerce → Settings → Emails Ensure emails are enabled and recipients are correct.

6) Slow WooCommerce Store (Feels “Buggy” but It’s Performance)

Sometimes the “bug” is just a slow site causing timeouts, broken AJAX calls, and abandoned carts.

Symptoms

  • Product pages take 5–10 seconds
  • Admin slow when editing products
  • Checkout spinner never ends
  • Random timeouts on inventory updates

Usual causes

  • Heavy page builders + bloated theme
  • Too many scripts
  • Unoptimized images
  • Slow database queries
  • WooCommerce transients bloated
  • No object caching (Redis/Memcached)

Fix checklist

✅ Measure speed properly Use:

✅ Enable object cache (Redis) If your host supports it, Redis can massively reduce load.

✅ Optimize product images

  • Use WebP
  • Compress images
  • Lazy-load below fold

✅ Clean expired transients WooCommerce stores can accumulate junk transients. Plugins like WP-Optimize can help.

✅ Check slow query logs Hosts often provide database performance tools.

7) Database Issues (Orders Missing, Stock Wrong, “Tables Need Update”)

Symptoms

  • Stock not reducing properly
  • Orders “disappear” in admin (but exist in DB)
  • WooCommerce prompts database update
  • Reports not matching actual sales

Usual causes

  • Incomplete database update
  • Corrupted tables
  • Plugin writing bad meta fields
  • Cron failing (background tasks not running)

Fix checklist

✅ Run WooCommerce database updates WooCommerce → Status → Tools Look for “Update database” options.

✅ Check Action Scheduler WooCommerce uses Action Scheduler for background tasks. Go to: WooCommerce → Status → Scheduled Actions If you see a backlog of failed tasks, that’s a smoking gun.

Action Scheduler docs: https://actionscheduler.org/

✅ Fix WP-Cron If WP-Cron is unreliable, set up a real server cron. Many hosts have a “Cron Jobs” section.

How to Find Plugin Conflicts Without Losing Your Mind

Plugin conflict hunting doesn’t have to be chaos.

The clean method (on staging)

  1. Switch to a default theme (Storefront is perfect).
  2. Disable all plugins except WooCommerce.
  3. Test the bug.
  4. Re-enable plugins in small batches (3–5 at a time).
  5. When it breaks, you’ve found the conflict group.
  6. Narrow it down to the single plugin.

Typical conflict culprits

  • Caching/minification plugins
  • Security/firewall plugins
  • Coupon/discount rule plugins
  • Page builders
  • Custom checkout field plugins
  • Currency switchers
  • Translation plugins (sometimes with dynamic strings)

Theme Bugs: WooCommerce Template Overrides Gone Wrong

Themes often override WooCommerce templates inside:

/wp-content/themes/your-theme/woocommerce/

When WooCommerce updates, some overridden templates become outdated and can break functionality.

How to check

WooCommerce → Status → look for “Templates” section It will list overrides and whether they’re outdated.

Fix options

  • Update the theme
  • Replace outdated templates with current WooCommerce versions
  • Use a child theme and keep overrides minimal

If your theme is old or heavily customized, consider switching to a WooCommerce-friendly theme that updates consistently.

Security and “Invisible” Bugs (403 errors, blocked checkout, REST failures)

Security plugins and firewalls can break WooCommerce in sneaky ways.

Symptoms

  • REST API errors in WooCommerce Status
  • 403 forbidden during checkout
  • Admin-ajax requests blocked
  • Payment gateway callbacks failing

Fix checklist

✅ Temporarily disable the security plugin and test ✅ Whitelist WooCommerce endpoints (/wp-json/, admin-ajax.php) ✅ Review server firewall logs (your host can help)

Update Strategy: Stop Bugs From Coming Back

Updates are necessary, but unmanaged updates are where stores get hurt.

A safer update routine

  1. Clone to staging

  2. Update WordPress core

  3. Update WooCommerce

  4. Update extensions

  5. Test critical flows

    • Add to cart
    • Coupon
    • Checkout (each payment method)
    • Account login / password reset
    • Order email sending

  6. Push to live

Pro tip

Avoid updating everything at once on production. That’s like changing the engine while driving downhill.

Store Stability Checklist (Bookmark This)

Use this checklist when you need to fix WordPress and WooCommerce bugs quickly:

  • Full backup taken
  • Bug reproduced + documented
  • Debug log enabled (WP_DEBUG_LOG)
  • WooCommerce logs checked
  • WooCommerce Status checked (templates, REST, cron, memory)
  • Cache excluded for cart/checkout/account
  • JS minification tested off
  • Plugin conflict test performed
  • Theme override status reviewed
  • Payment gateway logs + webhooks confirmed
  • SMTP configured for emails
  • Scheduled Actions backlog cleared
  • Performance tested (PSI/GTmetrix)

FAQs (Real Questions Store Owners Ask)

Why does my WooCommerce checkout stop working after an update?

Most commonly it’s a plugin conflict, outdated theme template override, or caching/minification breaking checkout scripts. Check WooCommerce logs and test with caching/minify disabled first.

What’s the fastest way to find which plugin is causing the bug?

Disable all plugins on staging except WooCommerce, then re-enable in batches. When the issue returns, narrow down to the specific plugin.

Why is my cart showing wrong totals or not updating?

Cart/checkout pages should never be cached. Exclude them from caching and disable JavaScript optimization temporarily to test.

Why are WooCommerce emails not sending?

Because WordPress email delivery can be unreliable without SMTP. Set up WP Mail SMTP with a proper email provider like SendGrid or Mailgun.

How do I fix “There has been a critical error on this website”?

Enable debug logging, check debug.log, increase PHP memory, and disable plugins via FTP. It’s usually a PHP fatal error caused by an incompatible plugin or theme.

What causes WooCommerce to be slow in the admin?

Often database bloat, too many plugins running heavy queries, or lack of object caching. Checking scheduled actions and enabling Redis can help a lot.

Final Wrap-Up

WooCommerce bugs feel stressful because they hit the exact places that matter: cart, checkout, payments, and order processing. But if you use a repeatable approach—logs first, isolate conflicts, fix caching rules, verify server resources—you’ll stop guessing and start fixing.

Here’s the main takeaway: don’t treat bugs like mysteries. Treat them like systems. Every bug has a trigger, an error trail, and a root cause.

If you want the biggest immediate wins, start here:

  • Exclude cart/checkout/account from caching
  • Disable JS minify/combine to test
  • Check WooCommerce logs + debug.log
  • Run a clean plugin conflict test on staging
  • Set up SMTP so emails don’t “randomly” fail

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