Checkout fails for only some visitors

Uptime checks can stay green while a browser, market, payment method, or consent state blocks part of the purchase path.

Typical symptoms

• Conversion falls without a complete outage.
• Support cases cluster around one browser, device, market, or payment method.
• Add-to-cart, cart updates, or checkout navigation fail intermittently.
• The issue starts after a theme, app, tag, or checkout change.

What to capture

Record the URL, exact journey, product, browser, device, market, consent state, payment method, time window, console and network output, storefront events, release history, and approved test setup.

Don't assume

A recent release may be related without being the cause. A healthy homepage and successful orders from other visitors do not clear the affected path.

Steps

1. Build the smallest matrix that can reproduce the report.
2. Find the exact step where expected and actual behavior diverge.
3. Inspect page state, requests, console errors, focus, and button state.
4. Compare failing and passing conditions.
5. Narrow the issue to a theme, app, service, configuration, or provider.
6. Apply one approved fix and rerun the same path.

Done when

• The original conditions have been retested.
• The path works in the affected browser, market, or payment state.
• Monitoring covers the step that failed.
• The report distinguishes the observed failure from the proposed cause.