Troubleshooting Pixel & Tracking Tag Issues

Guideline

Troubleshooting Pixel & Tracking Tag Issues

GTG CRM Team

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Pixels and tracking tags are the foundation of modern digital advertising. Using pixels and tracking tags, you can accurately measure conversions, build retargeting audiences, and optimize campaigns based on reliable data. When tracking fails, the entire backend system is affected: inaccurate metrics, audience growth, and inaccurate ad performance evaluation.

This document compiles the most common tracking errors with Facebook Pixel and Google Tag, explains the causes, and provides systematic instructions on how to check and fix them.

Common problems with Facebook Pixel

Pixel not found

This is the most common error when Facebook fails to detect pixels on a website. Common signs include Pixel Helper reporting "No pixels found," the audience file not growing, and Events Manager not recording any events.

The most common cause is that the pixel is not installed, installed in the wrong location, or using the wrong Pixel ID. The pixel must be within the <head> tag, load on all pages, and not be blocked by other scripts.

Additionally, you should check for JavaScript errors in your browser. Any errors that disrupt page loading can cause the pixel to malfunction.

Pixel is working, but there are no events in Events Manager.

In some cases, Pixel Helper reports that the pixel is running, but Events Manager doesn't display new data.

First, be patient. Data processing may take up to 20 minutes. For immediate testing, use the Test Events tool.

If the event is still not visible, you need to check domain verification and deduplication configuration when using Pixel and Conversions APIs simultaneously. If event_id is not set correctly, Facebook may discard or not record the event.

Lack of Standard Events

PageViews are active, but AddToCart, Lead, or Purchases aren't being recorded, usually because these events weren't triggered at the right time.

Unlike PageView, standard events must be explicitly called at each specific user action, for example, adding to cart, submitting a form, or completing a checkout.

Ad blockers can also block browser-side tracking. To mitigate this risk, it's advisable to implement the Conversions API as an additional server-side tracking layer.

Tracking has dropped significantly after iOS 14.5+.

If conversion numbers drop suddenly, the audience file shrinks, or attribution becomes unstable, the cause is often due to privacy changes on iOS.

The solution includes implementing a Conversions API, configuring Aggregated Event Measurement, verifying the domain, and adding UTM parameters to support cross-platform measurement.

Common problems with Google Tags

Google Tag not found

When Tag Assistant doesn't detect a tag, conversion tracking and remarketing won't work.

You need to verify that the tag is correctly set and that the Conversion ID in the code matches the ID in Google Ads. If using Google Tag Manager, make sure the tag has been published and the trigger is configured correctly.

Tags display alerts in Tag Assistant

The tag can display a yellow or red status:

Green: operating normally
Gold: minor error, should be checked.
Red: Serious error, requires immediate attention.

Common warnings include duplicate tags, missing conversion values, or incorrect configuration. Most can be fixed by removing duplicate code and adding the necessary parameters.

Remarketing audience growth is not increasing.

If the remarketing file is consistently zero or "too small to use," the remarketing configuration and actual traffic need to be checked. New files need 24 to 48 hours to start collecting data and must reach a minimum threshold before use.

Dynamic remarketing is not working.

General ads that display instead of the correct product are often due to a mismatch in product IDs between the tag and the feed. The ID sent from the tag must absolutely match the ID in Merchant Center. The feed needs to be approved and the correct business type selected.

General tracking issues

CORS errors and security policy

CORS errors or Content Security Policy issues can block script tracking without being obvious. Websites need to use HTTPS and allow full domain tracking in the security header.

Ad blockers block tracking.

Approximately 25–30% of users use ad blockers. This is an unavoidable reality.

The most sustainable solution is to combine server-side tracking with transparency with users regarding data collection.

Tracking across multiple subdomains

If the user journey spans multiple subdomains, cross-domain tracking needs to be configured to avoid session interruptions and attribution discrepancies.

Check and confirm tracking.

Before running ads, always test the tracking:

With Facebook: Pixel Helper, Test Events, and audience file inspection.
With Google: Tag Assistant, real-time reporting, and conversion testing.
With GTM: use Preview mode to test the trigger and firing order.

Conclude

Tracking errors rarely stem from a single cause. Most often, they arise from missing configurations, script conflicts, or changes to browser privacy settings.

By taking a systematic approach that combines browser tracking and server-side tracking, you can maintain accurate data and ensure that all advertising decisions are based on reliable measurement.