Why Google Tag Assistant shows errors (and which ones matter)
Google Tag Assistant is great for debugging, but it flags a lot, and not every warning means your tracking is broken. Knowing which errors are real problems and which are noise saves you chasing ghosts.
What Tag Assistant is actually checking
Tag Assistant connects to your site and reports which tags fired, in what order, with what data. It flags tags that did not fire, fired with missing values, or fired more than once. It is the fastest way to confirm whether your GTM tags are behaving.
Errors that matter
- Tag did not fire on a page where it should: a real not-firing problem.
- Multiple instances of the same tag: duplicate tags, which inflate your data.
- Missing required fields like a purchase with no value: a data layer gap.
Warnings you can usually ignore
Tag Assistant often flags third-party tags it does not fully understand, cosmetic ordering notes, or consent-related warnings that are expected when a tag is correctly held back until consent. The skill is matching each flag to behaviour: if the tag fires once, on the right page, with the right data, a yellow warning next to it is probably noise. If in doubt, confirm the same thing in GA4 DebugView, which shows what GA4 actually received.
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