HTTP 403 When Downloading IAP Content Hosted by Apple

I enabled content hosting for one of my IAP items. However when I try to purchase and downloading data, if the request IP is in mainland China, the iosapps.itunes.apple.com server will return 403 and the download will fail. If the IP is outside of mainland China, it WAI. The DNS servers in mainland China will return IP also in mainland China. So I'm sure it is not because of firewall in China. Is the hosted content not available in App Store CDNs in mainland China?