This article will help you:
  • Figure out why your page isn't loading in the Editor
  • Figure out why your page is loading slowly, or the original "flashes" briefly before the variation appears
  • Figure out why you can't see the changes you made rendering on your page
  • Figure out why your changes are appearing, but not as you intended
  • Figure out why your goals aren't tracking correctly (or at all)

We work hard to make Optimizely delightful and seamless for you, but sometimes technology doesn’t work the way you expect it to. For those less happy times, we’ve created this guide to empower you with a framework and techniques for solving problems. With these techniques, you’ll be able to solve many problems without additional help and feel like a hero doing it.


Your experiments are more likely to be effective if you follow the best practices for setting them up. Learn the basics in our Getting Started Guide and the best techniques for QAing experiments in our Pre-Launch Checklist Guide.

Before you start an experiment, you’ll always want to preview it to make sure that it’s working as intended. Check your site’s existing functionality, as well as new elements you’ve added, and navigate to the events tab to make sure that your goals are firing correctly.

If everything looks good, then start running your experiment. If not, check this article to help diagnose the issue. There are a few common reasons you’ll need to troubleshoot:

  • Your page isn't loading in the Editor. We have a whole article with common Editor loading issues. Check it out to diagnose your issue and get your page to load correctly.
  • Your page is loading slowly, or your original page "flashes" briefly before the variation appears. You may notice this when you try to view your experiment live on your site. This often has to do with the timing of Optimizely's execution on the page. See our load time/flashing article for more information.
  • You don’t see any changes on the page. You may notice this when you preview the experiment. More often you will set your experiment live and visit a page you expect to modify, but find that your changes aren't appearing. This could be an issue with experiment activation or variation content.
  • The page isn’t displaying as you intended. You’ll also notice this when you preview the experiment. This could be an issue with variation content, or it could be an issue with the way the browser is rendering Optimizely's changes. Watch our video or read our article on Editor Best Practices to learn more about how to make more precise changes in the Editor.
  • A goal/event isn’t tracking correctly. You may notice this when you preview, but you might also catch it as results are coming in. See our article on troubleshooting goals for more information.
  • You don't see conversions for a certain variation on the Results page. This is likely an issue with variation content.
  • You don't see ANY visitors or conversions on the Results page. This is likely an issue with experiment activation.

We hope that these techniques will empower you to solve these issues.