Service Update: We're happy to let you know that service is now back up in China. After investigating ourselves and talking to our service provider, AWS, we found that the DNS (one of our servers) we used was being blocked. That particular DNS server was also being used by other services, so we're unsure of why it happened. But the good news is, we switched over to a new DNS server and you should be able to access Wunderlist sync again. Thanks so much for being so patient while we sorted this out!
We are getting reports that www.wunderlist.com and our sync service is currently sometimes not accessible in China, despite all of our servers being online. We are currently investigating to see where the issue is and will update everyone as soon as we know more.