Cannot access Google Cloud Compute Instance External IP

If you already verified that Google Firewall or your VM are not blocking packets, you must make sure that VNC service is configured to listen on the external IP address.

You can always use a utility like nmap outside Google project to reveal information on the port status.

The Google Cloud Compute instance was set, by default, to not allow HTTP traffic. I reset the configuration to allow HTTP traffic. I then tried the troubleshooting tip to run a small HTTP service in python. I was able to get a response from the service over the internet.

As such, the original question is answered, I can access Google Cloud Compute Instance External IP. My wider issue is still not solved, but I will post a new, more specific question about this issue

enable http/https traffic form the firewall as per the need. it will work!!

TLDR: make sure you are requesting http not https

In my case i was following the link from my CE instance's External Ip property which takes you directly to the https version and i didn't set up https, so that was causing the 'site not found' error.