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google-app-enginegoogle-cloud-platformcustom-domain

Google cloud App engine Custom domain ERR_CONNECTION_CLOSED

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:

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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

Solution

  • I managed to repeat exactly the same setup with another subdomain (on totally different domain). I had issues with geeting Google-managed certificate - it took the App Engine a really long time to install it. But at the end it worked.

    So it looks like the issue is indeed with Google and the certificate. I'll wait and let you know if this was the issue.

    Edit (additional explanation): it turns out that the issue is with the client's domain which doesn't allow another CAA (in this case Google or Let's encrypt) to issue a certificate.