Replace “the shop is broken” with one action.
Name the page, user and action. Does the cart fail for everyone or only after one coupon? Can a customer still buy another product? Separate a missing layout element from a failed request or an unexpected payment outcome.
Record the last known working moment and the first observed failure. Keep customer secrets and payment credentials out of a public support request. The useful evidence is the symptom and the route to reproduce it, with private references shared through the appropriate support channel.
Look at the change without assuming the cause.
Compare recent plugin, theme, PHP and configuration changes. A scheduled job or external service may have changed at the same time as the visible update. Ask who made each change and which environment was affected.
A conflict means components interact badly; a component can also fail on its own. A developer can isolate those possibilities by repeating the same action with controlled changes. The official WooCommerce conflict-test process provides the method; the owner’s job is to make the customer impact clear.
Give the investigation a usable starting point.
The example below is fictional. It describes one failed cart action without claiming that the updated plugin is responsible.
| Question | Example answer |
|---|---|
| What did you expect? | Adding the selected cap keeps the tee in the basket |
| What happened? | The basket displayed a loading indicator and did not refresh |
| How can it be repeated? | Select tee M, add it, then add the cap on mobile |
| What changed? | An extension update this morning; cause not established |
| What needs checking? | Repeat the same steps on staging and inspect the failed request |
Verify recovery before returning to normal work.
Agree who can change the test environment and how it will be restored. Keep test payments, mail and fulfilment isolated from the live business. A staging copy should be useful for the failure, rather than merely being an old copy with unrelated settings.
After the proposed fix, repeat the failed route and an ordinary route that previously worked. Check what reaches the order and customer. A page opening successfully is not enough if checkout or follow-up still fails. Use the checkout guides when the incident affects purchasing.