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Optimizely Knowledge Base

Troubleshooting: No traffic in an experiment

  • Figure out why you see no traffic on your Results page
  • Figure out why you see zero visitors in a certain variation
  • Check that visitors are entering your experiment

Are you experiencing any of the following issues? Use this article to troubleshoot your experiment setup.

  • You aren't seeing any traffic on the Results page, even an hour or two after you launch the experiment

  • You aren't seeing visitors in a certain variation on your Results page

Here's when this article may not be for you:

1. Check the snippet and experiment status

Before you begin this troubleshooting process, quickly make sure that the Optimizely Snippet is on your page, as high as possible in the <head> tag, and that there is only one Optimizely Snippet on the page.

Optimizely works best when installed directly in the <head> tag of every page you would like to test. Having more than one Optimizely Snippet on the page, even if it’s for a different project, can create complications.

2. Check targeting issues

Next verify that your targeting conditions are set correctly: audience conditions, URL Targeting conditions, or traffic allocation. Double-check each of these in Optimizely for obvious errors that would be preventing you from seeing the experiment.

First, test your URL Targeting conditions.

Once you’ve done that, try the following: 

  1. Use the Optimizely Log. This is will show you all of Optimizely’s actions and decisions. 
    Append the ?optimizely_log=info query parameter to your URL to read the log. Then, reload the page.

  2. Filter the log by your Experiment ID. Paste your Experiment ID into the search field:

    Optimizely logs

  3. Check whether the log reveals any Condition errors -- in other words, that you failed to match URL, Audience, or Traffic Allocation conditions.

    If you’ve failed conditions, and you don’t think you should be failing them, there is a problem with your URL Targeting, Audience, or Traffic Allocation configuration. You’ll need to change them in Optimizely.

    If you passed the conditions but you’re still not seeing your experiment, move on to the next section on other issues.


In Optimizely, we've updated the client so you must append the optimizely_log parameter, then reload the page to see the log. This minimizes the logging overhead for visitors and pageviews that don't request the log.

Still having trouble? Reach out to support for assistance.