Tag Monitor reports a tag as an error when Google Tag Manager itself reports that the tag failed. This page explains when that happens, and which situations are not counted as errors.
- How Code-Cube.io decides a tag failed
- What is not counted as an error
- Tags interrupted by a page unload
- Vendor-specific behavior
- What to do when a tag fails
- Next steps
How Code-Cube.io decides a tag failed
Code-Cube.io relies on the result GTM reports for each tag. A tag counts as an error when GTM flags it as failed, through data.gtmOnFailure(). GTM does this in four situations:
Situation | What happens |
Runtime error | The tag's code throws an error while it runs |
Permission denied | The tag tries to do something the GTM sandbox doesn't allow |
Timeout | The tag takes too long to finish |
Failure reported by the template | The tag template itself calls data.gtmOnFailure() |
In all other cases, the tag counts as a success.
What is not counted as an error
Tags interrupted by a page unload
If a tag starts firing but the page unloads before the tag finishes, for example because of a redirect, Code-Cube.io does not flag it as an error. These tags are not logged at all.
Vendor-specific behavior
Code-Cube.io has no special logic for specific vendors. Meta tags, for example, are treated exactly like every other tag, even when a redirect is about to happen.
What to do when a tag fails
When Tag Monitor detects failing tags, the Tag Debug Assistant helps you fix them. It gives each broken tag a severity level, the plausible root cause, the possible business impact, and potential fixes. See 
Tag Debug Assistant.
Next steps
Understanding & solving errors: learn how to read and fix the errors Tag Monitor reports
Notifications & alerts: choose where and how you receive alerts
Questions? Email support@code-cube.io.