I'm doing a server-side GTM setup. I managed to set up a Google cloud App engine.
I added a custom domain (verified with Google webmaster central, added DNS records etc.).
I can see in the Cloud settings that the custom domain (actually it's a subdomain) is set up, using also Google-managed, auto-renewing SSL.
So, everything looks fine except when I try to access this custom domain (directly or while doing a GTM container preview), I get the connection error in the browser (ERR_CONNECTION_CLOSED).
Since all DNS records looks OK (I have TXT record for the GWC/ownersip verification, 4 A records and 4 AAAA records for Google cloud) I did a tracert where I can see that it gets to the google server (hop 5), but then it gets lost:
The last hop should be the subdomain, but it's a "random" Google server).
It's more than 24 hours from the DNS records change so I don't believe it's a DNS propagation issue (although it still might be of course but the chances are very small). So if anyone has any idea, what could be wrong, I'd be very glad :D