I have set up a folder in boxcn and shared it with collaborators in China. When I create a link to an Excel or Word file and send it to them, and they click on the link, instead of seeing a file preview, they see a message:
"Service Unavailable: We are currently experiencing technical difficulties. Please try again later."
Trying again later does not help. We have been using Box for collaboration with China for many years and did not see this issue on boxcn until recently.