Monitoring Error Log Variable Troubleshooting

Learn how we bucket data layer variables into severity for troubleshooting.

Do you have a list of variable errors in your Error log but wondering:

  • What should take priority on fixing
  • What should I be concerned about affecting my marketing campaigns
  • How to go about fixing these

Let's start with prioritizing common variables. Take a look at the list below broken out to high, medium, and low priority.

High Priority Variables

If you see any errors in your account with the ones below then we highly suggest investigating and fixing right away. These are frequently used in most tags like Facebook, AdWords, etc.

Medium Priority Variables

Low Priority Variables

Note: keep in mind that these can vary by company. Be sure to check with your marketing team on what data that they are leveraging in audiences, conversion tracking, and analysis to be sure you prioritize your own variables properly.

How to Fix Broken Variables

This will vary depending on your unique configuration and frankly the change that may have impacted the data layer.

Here are common reasons why variables return empty data:

  • Casing issue with the dataLayer vs the variable in GTM. For example: visitorType is the variable name in GTM but VisitorType is in your dataLayer (notice the capital V difference). This will throw an error (and was previously an issue in one of our own containers!)
  • The tag with the variable triggers before the dataLayer is populated. For example lets say you set Facebook product detail view to be on a "Page View" trigger. Chances are the dataLayer is not populated until after the "Page View" trigger executes. So the variable is undefined.
  • Javascript error breaking dataLayer.
    • If you aren't using our sitewide JS error tracking container then be sure to import that to your GTM account to track these errors for you in Google Analytics.
  • DataLayer was removed from website
  • Conflicts with third party scripts or features
  • Product data doesn't exist for particular product (ex. no product type)

Have questions on your own variable errors? Let us know so we can help!