I run a website that allows you to hire a journalist anywhere in the world, and we have correspondents in 150 countries. It's hosted on App Engine, and occasionally we get a journalists emailing us to say that our site is not available from where they are. The specific error is:
Your client does not have permission to get URL xxx from this server. (Client IP address: x.x.x.x)
We're sorry, but this service is not available in your country. That’s all we know.
The locations we have identified so far are: Cuba and Crimea.
I can't find a complete list anywhere, but I really need one. Any suggestions?
There is not an official list. I would recommend using this list until one specifically for App Engine is created.
Even though there is no documentation on this topic, I do not believe the Google Cloud Platform is the root cause of what your users are experiencing. Some of Google AppEngine apps are properly serving traffic to IP addresses geo localized in some of the countries mentioned in the other answers. Specifically, I know serving to North Korea, Iran, Cuba is working.
The problem we are seeing is usually the opposite: some countries blocking some Google owned subdomains (appspot.com, googleapis.com, etc.) or IP ranges owned by the Google Cloud Platform.