Tag Assistant forces preview on main domain instead of subdomain (RD Station Landing Page
Hi everyone,
I'm facing a weird issue with Google Tag Manager Preview Mode / Tag Assistant when trying to debug a subdomain tracking setup.
Here is my current scenario:
- Main Domain: dgt.com.br (has its own GTM container)
- Subdomain: materiais.dgt.com.br (hosted on RD Station Landing Pages, has a separate GTM container: GTM-M7G9QZP)
The issue:
When I go to GTM, click "Preview", and explicitly type my subdomain URL (https://materiais.dgt.com.br/monitoramento-colaborativo), the Tag Assistant opens the page, but immediately switches the connected domain in the debug window to the main domain (dgt.com.br).
Because of this, it tells me "Google Tag GTM-M7G9QZP not found" because it's looking for the subdomain's container inside the main domain, where it obviously doesn't exist.
The GTM code is correctly hardcoded in both the HEAD and BODY of the RD Station Landing Page (subdomain). I can see other tags firing there (like GA4 through gtag), but the Tag Assistant debugger keeps forcing the session back to the apex/main domain during preview.
Has anyone experienced this behavior with subdomains or RD Station platforms? Is there a cookie conflict or a way to force Tag Assistant to stay locked on the subdomain without falling back to the main domain?
Thanks in advance!