9e0557eeac
New section in common_issues.md covering: - How RegEx Table content grouping works in GTM - Common pitfall: new page paths falling to "Other" - Gotcha: parallel Path/URL variables must stay in sync - JHR content group category reference table - Audit checklist for content grouping Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
8.5 KiB
Common GTM Issues & Fixes
Container Issues
GTM Not Firing
Symptoms: No GTM requests in network tab Causes:
- Script blocked by ad blocker
- Script placed after closing body tag
- JavaScript error before GTM loads
- Consent management blocking GTM
Fix:
<!-- Place immediately after opening <head> tag -->
<script>(function(w,d,s,l,i){...})(window,document,'script','dataLayer','GTM-XXXXXX');</script>
Multiple Containers Conflict
Symptoms: Duplicate events, inconsistent data Causes:
- Legacy container not removed
- Different teams installed separate containers
- Theme/plugin auto-installed GTM
Fix:
- Audit all containers in source
- Consolidate to single container
- Use GTM environments for staging/prod
Container ID Mismatch
Symptoms: Tags not firing, wrong property receiving data Causes:
- Dev/staging container on production
- Copy-paste error during installation
Fix: Verify container ID matches GTM account
DataLayer Issues
DataLayer Not Initialized
Symptoms: First push events lost Code Error:
// Wrong - GTM loads before dataLayer exists
<script>GTM snippet</script>
dataLayer.push({...});
Fix:
// Correct - Initialize dataLayer first
<script>window.dataLayer = window.dataLayer || [];</script>
<script>GTM snippet</script>
Case Sensitivity Issues
Symptoms: Triggers not matching Example:
// DataLayer pushes "AddToCart"
dataLayer.push({ event: "AddToCart" });
// But GTM trigger looks for "addToCart" - won't match!
Fix: Standardize event naming (recommend lowercase with underscores)
Wrong Data Types
Symptoms: Calculations wrong in GA4, missing data Example:
// Wrong - price as string
dataLayer.push({ ecommerce: { value: "29.99" }});
// Correct - price as number
dataLayer.push({ ecommerce: { value: 29.99 }});
Timing Issues
Symptoms: Events fire before data available Cause: DataLayer push happens after tag fires
Fix: Use "Custom Event" trigger instead of "Page View"
Tag Issues
Tag Not Firing
Checklist:
- ✓ Trigger conditions met?
- ✓ Trigger enabled?
- ✓ Tag not paused?
- ✓ No blocking triggers active?
- ✓ Consent mode not blocking?
Debug Steps:
- GTM Preview > Check Tags Fired
- Verify trigger shows green check
- Check Variables tab for expected values
Duplicate Tag Firing
Symptoms: Events counted 2x in GA4 Causes:
- Multiple triggers on same action
- Page re-renders triggering again
- SPA virtual pageviews firing multiple times
Fix:
- Add "Once per event" tag firing option
- Use trigger groups to control firing
- Add conditions to prevent re-firing
Wrong Parameters Sent
Symptoms: Data appears in wrong fields in GA4 Debug:
- GTM Preview > Tags > Show fired tag
- Check "Values" sent with tag
- Compare with expected parameters
E-commerce Issues
Missing Transaction ID
Symptoms: Duplicate purchases counted
Fix: Ensure unique transaction_id generated server-side
Items Array Empty
Symptoms: Revenue tracked but no products
Check: ecommerce.items array populated
Value Mismatch
Symptoms: Revenue doesn't match actual Causes:
- Tax/shipping included inconsistently
- Currency conversion issues
- Discount applied incorrectly
Purchase Event Fires Multiple Times
Symptoms: Same order tracked 2-3x Causes:
- Page refresh on confirmation
- Browser back button
- Email link revisit
Fix:
// Check if already tracked
if (!sessionStorage.getItem('purchase_' + transaction_id)) {
dataLayer.push({ event: 'purchase', ... });
sessionStorage.setItem('purchase_' + transaction_id, 'true');
}
Consent Mode Issues
Tags Blocked by Consent
Symptoms: Tags show "Blocked by consent" in Preview Fix:
- Verify consent mode implementation
- Check default consent state
- Test with consent granted
Consent Not Updating
Symptoms: Tags stay blocked after user accepts
Fix: Verify gtag('consent', 'update', {...}) fires on accept
SPA (Single Page App) Issues
Pageviews Not Tracking Navigation
Symptoms: Only initial pageview tracked Cause: No page reload on route change
Fix: Implement History Change trigger or custom event:
// On route change
dataLayer.push({
event: 'virtual_pageview',
page_path: newPath,
page_title: newTitle
});
Events Fire on Old Page Data
Symptoms: Wrong page_path in events Fix: Update page variables before event push
Content Grouping Issues (RegEx Table Variables)
How Content Grouping Works in GTM
Content grouping uses RegEx Table variables to categorize pages by URL/path patterns.
The variable takes an input (typically {{Page Path}} or {{Page URL}}), tests it against
an ordered list of regex patterns, and returns the first matching output value.
If no pattern matches, it falls to the Default Value (usually "Other").
Key settings:
- Full Matches Only: OFF — partial regex match is sufficient
- Capture Groups and Replace: OFF — output is the literal value, not a regex replacement
- Ignore Case: ON — case-insensitive matching
New Page Paths Fall Through to "Other"
Symptoms: New sections (campaigns, special events, landing pages) show as "Other" in GA4 content group reports.
Root cause: The RegEx Table was built for the site's original URL structure. New paths like /specialEvent/, /campaign/, /timesale/ don't match any existing pattern.
Example: JHR site has /specialEvent/landersshoppingfesta2026/teaser.do but only /package/ and /event/ are in the regex table, not /specialEvent/.
Fix: Add regex rule for the new path pattern. Place it BEFORE the default.
Gotcha — two variables to update: Sites often have parallel content group variables:
- Page Path based (e.g.,
(\/m)?\/specialEvent\/(.*)) — for internal reports - Page URL based (e.g., full URL with domain regex) — for cross-domain or subdomain tracking
Both must be updated or they'll produce inconsistent groupings.
RegEx Pattern Conventions (JHR Example)
Page Path patterns follow this structure:
(\/m)?\/section\/(.*) → Korean Category Label
(\/m)?— optional mobile path prefix\/section\/— the URL path segment to match(.*)— match anything after
Page URL patterns include domain matching:
^https\:\/\/(www|app|jpg|gjb|gjj|grp|\.)?josunhotel\.com(\/m)?\/section\/(.*)
- Multi-subdomain support via alternation group
- Same
(\/m)?mobile prefix handling
Content Group Categories (Hospitality Reference)
| Pattern | Category (KR) | Category (EN) |
|---|---|---|
/intro.do, /main.do |
메인페이지 | Main Page |
/about/, /press/ |
기업 소개 | Corporate Info |
/hotel/ |
호텔 소개 | Hotel Info |
/rooms/ |
객실 소개 | Room Info |
/dining/ |
다이닝 이용 | Dining |
/facilities/, /meeting/, /fitness/ |
부대시설 소개 | Facilities |
/package/, /event/ |
이벤트 | 패키지 조회 | Events & Packages |
/specialEvent/, /timesale/, /campaign/ |
캠페인 | 프로모션 | Campaign & Promotion |
/activity/ |
액티비티 소개 | Activities |
/step[0-4] |
룸, 패키지 예약 프로세스 | Booking Process |
/resve/dining/ |
다이닝 예약 프로세스 | Dining Booking |
/membership/ |
멤버쉽 | Membership |
/mypage/, /login/, /join/ |
웹회원 관련 | Member Portal |
/retail/, /product/, /office/ |
리테일 관련 | Retail |
/voc/, /customer/ |
고객지원 | Customer Support |
/policy/ |
웹사이트 정책 | Website Policy |
/upload_file/event/html/ |
캠페인 | 프로모션 | Campaign & Promotion |
| Default | Other | Other |
Audit Checklist for Content Grouping
- Run
dtm var info <var_id>to dump the full regex table - Check if new site sections have matching patterns
- Verify both Path and URL variables are in sync
- Check GA4 config tag references the correct variable
- Test in GTM Preview: navigate to new page, check variable value
- After update, verify in GA4 Realtime > Content Group report
Performance Issues
Tags Slowing Page Load
Symptoms: High LCP, slow TTI Causes:
- Too many synchronous tags
- Large third-party scripts
- Tags in wrong firing sequence
Fix:
- Use tag sequencing
- Load non-critical tags on Window Loaded
- Defer marketing tags