Payments failing for some customers and not others, orders that never arrive, or a checkout that reports success and then nothing happens. WooCommerce problems are rarely where they appear to be.
What it usually looks like
- Payment declined for some cards and fine for others
- An order goes through but no confirmation email arrives, and nothing is logged
- A security or verification error on the checkout page itself
- Orders missing from the admin even though the customer was charged
- Subscriptions that stop renewing without anyone noticing
What actually causes it
- A page cache serving a stale nonce, so the checkout fails verification for logged-out visitors
- A cookie consent plugin holding back the WooCommerce session cookie until someone accepts, which breaks the session mid-checkout
- SCA and 3D Secure handling, where European cards need a step the theme is not handling
- Gateway API keys still pointing at test mode, or a webhook that never got set up
- HPOS enabled with something else still reading the old order tables
- Transactional email failing at the server rather than in WordPress
What I do
Reproduce it properly first, across a matrix of logged in and logged out, cookie banner accepted and ignored, and different payment methods. That establishes the real trigger rather than the reported one. Then it is the WooCommerce logs and the gateway dashboard side by side, matched on timestamp.
Subscription data is the one thing on a WooCommerce site you genuinely cannot recreate, so nothing goes near it without a verified backup first.
What it costs
Diagnosis is a fixed £150. You get the actual cause in writing, whether anything is recoverable, and what fixing it takes. The repair is quoted after that, once I know what I am dealing with. Nothing gets touched before there is a verified backup. More on how it works.