Common issues

Find your symptom, check the cause, apply the fix. Turn on debug mode first, because the console output usually names the reason directly.

The snippet does not startCopy Anchor Link

The snippet stops silently in these situations. Some print a message in the console, even without debug mode.

The snippet is outdatedCopy Anchor Link

You published a change, but the page still behaves as before.

1. Wait for the Publishing … indicator in the top bar to disappear.
2. Allow for the cache time. See Snippet settings.
3. Compare ablyft.get('data').revision with Snippet revision in Settings → Snippet. If they differ, the browser still uses an old copy. Reload the page with a hard refresh.
4. Check that you load the right file: an environment with a sub-snippet has its own file, such as …/s/12345678-staging.js.
5. If your own server or a CDN sits in front of the snippet, make sure it does not cache the file for longer.

While debug mode is on, snippet caching is turned off, which is helpful while you test.

FlickerCopy Anchor Link

Flicker means visitors briefly see the original page before the variation appears.

• Load the snippet synchronously and as early as possible in the <head>, before large scripts and stylesheets. Avoid async for the snippet. See Embed the snippet.
• Keep the Anti-flicker mode at Use built-in mode (Settings → Snippet). The snippet then hides the page right after it started and shows it again after all experiments have been applied, after 2 seconds at the latest.
• If the page stays blank for 2 seconds, an experiment waits for something that does not happen (for example an element that never appears). Check the console for errors.
• With Use your own custom mode, ABlyft does not hide anything. You have to hide and show the page yourself.
• Slow changes caused by a long chain of redirects or by content that loads late cannot be fully hidden. Ask your developer to check the load order.

Selectors do not find elementsCopy Anchor Link

Variation changes use CSS selectors. If an element is not on the page yet, ABlyft waits and applies the change when it appears. For your own code, use the same approach:

ablyftTools.waitForElement('.promo-banner', function (element) {
  element.textContent = 'Free shipping today';
});

Check selectors in the console with document.querySelectorAll('your selector'). Selectors that include generated class names change with each release of your website. See Dynamic content.

JavaScript errors in experiment or variation codeCopy Anchor Link

Code of the project, of an experiment and of a variation is run by the snippet. An error in it is caught, so your website keeps working, but the rest of this code does not run.

• In debug mode, the error appears in the console as ABlyft # ERROR on EXPERIMENT <id>: <message> (or VARIATION).
• JavaScript rules for environments, pages and audiences that throw an error count as not matched. The console shows JS RULE with the message.
• Test the rule or the code in the console to find the faulty line.

Subscribe to the ablyftError event to report these errors to your own monitoring, see Verify the integration.

Consent blocks trackingCopy Anchor Link

If your project uses Prerequisites for tracking (for example a consent rule), ABlyft keeps data in memory and sends no events until the rule is met. Symptoms:

• Visitors get a new assignment on each page view, or experiments do not stay stable.
• No events appear in the Live Log, and Tracking Prerequisite Rules NOT met shows in the console.

Check that your consent manager calls enableTrackingConsent and read the state with ablyft.get('trackingConsentEnabled'). See Consent manager.

Single-page applicationsCopy Anchor Link

If experiments only work on the first page and not after navigation, the page is not checked again. Use a page with the trigger URL Change, enable Use SPA features in the project settings, or activate pages with ablyft.push({ eventType: 'activatePage', pageId: … }). See SPA navigation.

A goal is not measuredCopy Anchor Link

• Check the goal in preview mode with ablyft.get('pingedGoals'): if the goal appears, it fires correctly.
• Click goals: the CSS selector must match the clicked element or one of its parents, and the goal must be assigned to an active page. Also check for JavaScript errors on the page, because they can stop other scripts.
• Custom and revenue goals: the eventName must be identical to the API name of the goal. See Custom goals.
• Goal counted once: goals with the counting method One are sent only once per variation and visitor. To test again, delete the ablyft_tgoals entry in the configured storage (see Storage & privacy).
• Another domain: if the goal is on a different domain, configure External tracking domains, see Snippet settings.

The visitor keeps seeing the same variationCopy Anchor Link

That is intended. The assignment is saved in the configured storage (ablyft_exps, see Storage & privacy), and the visitor stays in the same variation. For tests, use a private window or delete the website data. Use ?ablyft_set_bucketing=… only if you must set an assignment by hand, see URL parameters.

Still stuck?Copy Anchor Link

Contact ABlyft support. Please send the URL of the page, the project and experiment ID, the output of ablyft.get('data') and the console output with debug mode turned on.

Next stepsCopy Anchor Link

• Verify the integration
• Preview & Live Log
• Troubleshooting guides for non-technical checks