In order to confirm that there are issues with IPs you're on in China, we need:
1. A traceroute to the domain to see the network path. The site may not actually be blocked in China, but could be a ISP issue or other, so we need to see if it is timing out early in the network path.
2. The results from a Great Firewall Checker.
3. A nslookup of the domain.Use the command nslookup yoursitename.com (replace your actual site where yoursitename.com is).
4. The type of content on your site. China does censor certain kinds of content, including pornography, gambling and certain political talk.