How to troubleshoot common issues with Convertcom experiments

A/B testing platforms like Convert.com are great—until something breaks, and your “simple” experiment turns into a wild goose chase. If you’re running into tracking glitches, flicker, or just plain weirdness with Convertcom experiments, you’re in the right place. This guide is for marketers, product folks, and developers who’d rather fix things the right way than waste hours guessing.

Let’s cut to the chase: Here’s how to troubleshoot the stuff that actually goes wrong, with none of the usual hand-waving.

1. Check If Your Experiment Code Is Even Loading

Before you get lost in data, make sure the basics are working.

  • Open your site in an incognito window.
  • Right-click, hit “View Source” or “Inspect,” and search for convert.com or convert.js.
  • If you don’t see it, your script isn’t loading—nothing else matters until you fix that.

What to do if it’s missing

  • Double-check your script placement: Convert.com wants its snippet just before the closing </head> or as high up as possible for speed.
  • Are you using a tag manager? Sometimes, triggers or variables break. Test with all tags paused except Convert.
  • Caching/CDN issues: Don’t trust your browser cache. Hard-refresh (Ctrl+Shift+R) or clear cache. Sometimes CDNs serve an old version.
  • Adblockers: Try with them off. Convert scripts are sometimes blocked.

Pro tip: If your script’s not present, none of the fiddly JavaScript debugging matters. Always check this first.

2. Diagnose Why Variations Aren’t Showing Up

So your experiment is running, but the page looks the same? Don’t panic—this is common.

Quick checklist:

  • Is the experiment active and published? Sounds obvious, but double-check. “Draft” or “Paused” means nothing happens.
  • Audience/targeting settings: If you set aggressive targeting (only for Chrome, only logged-in users, etc.), most visitors—including you—won’t see it.
  • QA Mode: Convert.com lets you preview variations. Use the QA links for each variation. If you can see them in QA mode but not live, it’s targeting.

Troubleshooting steps:

  • Remove all cookies (or use incognito). Experiments can bucket users and stick with one version.
  • Check URL rules. If you set the experiment to run on /pricing but you’re viewing /pricing/, it might not match.
  • Device targeting: Don’t forget, mobile/desktop rules matter. If you’re testing on desktop but the experiment’s set to mobile, you’ll see nothing.

What to ignore: Don’t waste time fussing with browser versions unless you’ve actually set a browser include/exclude rule.

3. Fix Tracking and Conversion Problems

You’re seeing traffic in Google Analytics, but Convert.com says “zero conversions.” Or maybe the opposite. Here’s how to actually debug it.

Steps to follow:

  • Check your goal setup in Convert.com. Are you tracking a click, a page view, or a form submit? Make sure your goal matches what users really do.
    • For click goals: The selector must actually match an element on the page.
    • For URL goals: Watch out for trailing slashes—/thankyou isn’t /thankyou/.
  • Test the goal yourself. Trigger the action (click, submit, visit) and see if it logs a conversion in real-time.
  • Inspect the browser console. Convert.com sometimes logs goal hits or errors in the console. Look for red errors or helpful debug messages.
  • Conflicting scripts: Multiple analytics tools tracking the same thing can create double-counting or missed events. Try disabling others and re-testing.

Pro tip: Don’t trust the “integration wizard” blindly. Sometimes it says “all good” but the selectors/URLs are off.

4. Tackle Flicker and Page Flash (FOOC)

You know when your test page loads, shows the original, then suddenly changes? That’s called FOOC (Flash of Original Content), and it tanks experiment validity.

What causes flicker:

  • Script loads too late: If Convert’s script loads after the page is visible, users see the original before the variation is applied.
  • Heavy or slow scripts: Tag managers, third-party scripts, and slow networks all make this worse.

How to actually reduce flicker:

  • Move the Convert script as high up as you can in the <head>. Earlier = better.
  • Use Convert’s “anti-flicker snippet.” This is a short bit of CSS/JS that hides or dims the page until the test logic runs.
    • It’s not pretty, but it’s better than a visible flicker.
  • Minimize tag manager delays: If you must use GTM, set Convertcom to fire as early as possible.

What doesn’t work: “Async” script loading always increases flicker. Don’t use it for A/B scripts unless you have no choice.

5. Deal with Single-Page Apps (SPAs) and Dynamic Content

SPAs (think React, Vue, Angular) are a headache for A/B testing tools. Changes in page content don’t always trigger a new experiment run.

How to adapt:

  • Use Convert’s Mutation Observers or re-trigger logic. Look for settings or custom code that re-applies experiments when the DOM changes.
  • Manual triggers: Sometimes you need to call Convert’s API to re-evaluate experiments on route changes.
  • Test on actual navigation: Click around your app and see if variations persist. Don’t just reload the page.

Ignore: Old-school page load event listeners. They don’t work for SPAs.

6. Sort Out Cross-Domain and Cookie Issues

You want to run experiments across subdomains (like www.example.com and app.example.com) or keep buckets consistent for logged-in users.

Watch out for:

  • Same-site cookies: Modern browsers restrict cookies between subdomains unless you set them with the right flags.
  • Domain settings in Convert: Make sure you’ve set up cross-domain tracking in the Convert project settings.
  • 3rd-party cookie blockers: Some privacy tools will break cross-domain bucketing—test with them off.

How to fix:

  • Set cookies on the “parent” domain: Use .example.com instead of www.example.com when setting cookies.
  • Check browser console for cookie warnings: Modern browsers will complain if cookies are misconfigured.

7. Debug Slowdowns and Site Performance

A/B tools can slow down your site if you’re not careful.

What to look for:

  • Network tab in DevTools: Is convert.js slow to load? That’s your bottleneck.
  • Script order: Every millisecond counts—put Convert before other heavy scripts.
  • Unnecessary experiments: Pause or delete old experiments. Too many running at once can stack up.

Pro tip: If you see more than a 200ms delay from Convert’s script, something’s wrong—contact support or check your network.

8. Get Reliable QA—Don’t Trust “It Works On My Machine”

QA is where most experiments go sideways.

Build a checklist:

  • Test in incognito and different browsers.
  • Try with and without adblockers.
  • Switch devices: Mobile, desktop, tablet—each can behave differently.
  • Check both variations: Sometimes only one is broken.

What often gets missed:

  • Logged-in vs. logged-out states.
  • Regional targeting: VPN into other countries if you’re geo-targeting.
  • Interaction with popups or other overlays. Modals often interfere with variation code.

9. Know When to Call Support (and What to Do First)

You’ve tried everything and it’s still broken. Before you send a vague ticket:

  • Gather console errors, screenshots, and details on what you’ve tried.
  • List browser, OS, and whether you’re using tag managers.
  • Include experiment ID and exact steps to reproduce.

You’ll get a real answer faster if you avoid “it’s just not working” and provide specifics.

Summary: Keep It Simple and Iterate

Troubleshooting Convert.com experiments isn’t rocket science, but it does reward a methodical approach. Start with the basics—script loading, targeting, and goals—before you dive into the weeds. Most problems have boring causes, not exotic ones. Don’t get distracted by edge cases until you’ve ruled out the obvious.

Above all: Make one change at a time, test, and keep notes. The simpler your setup, the fewer headaches you’ll have. And if all else fails, don’t be afraid to hit pause and revisit your experiment design. Sometimes, less is more.