i found this error when loading WebGL build in chrome - 64 bit.

Well, it's a configuration problem on your server. Either a security limitation or something else. The requests for the "WebGL.data" and "WegGL.datagz" files returned a 502 HTTP response code which indicates a problem on the server itself.

It's possible that the MIME type of the files is not recognised or allowed on that server.

Anyways it's clearly a problem on your server so you should direct your complains to your hoster.