Google Tag Not Firing? Step-by-Step Fix Guide

If your Google tag isn't firing, conversion tracking breaks — and Google Ads can't optimize reliably. The tricky part is that the failure can be in gtag.js or in Google Tag Manager (GTM) — and consent can make it look intermittent.

This page covers both implementations and focuses on the most common root causes: triggers, consent blocking, script loading order, and environment constraints like ad blockers or CSP.

Symptoms (what you see)

• Tag Assistant / preview says the tag didn't fire
• Conversions show in GA4, but not in Google Ads
• Tag fires on some pages but not on the conversion page
• Tag fires only after refresh / only for some users

Why it happens

• gtag.js not loaded: script blocked, wrong ID, async order issues
• GTM trigger mismatch: trigger conditions don't match real URLs/events
• Consent blocking: Consent Mode defaults/updates are wrong so tags never get permission
• Script loading order: consent defaults run too late or tags fire before consent state exists
• Ad blockers / CSP: browser extensions or Content Security Policy blocks Google endpoints

Fix checklist (gtag.js + GTM)

1. Check triggers: verify GTM triggers match the real conversion URL/event (not a staging URL)
2. Check consent blocking: confirm Consent Mode defaults run before tags and updates fire on accept/reject
3. Check script loading: ensure gtag.js / GTM container loads on the conversion page
4. Check blockers/CSP: test in a clean profile/incognito, and review CSP console errors

If you want the broader framework of why tracking breaks (beyond tag firing), read why Google Ads conversions break.