This page describes problems users or developers frequently encounter and gives solutions to those problems.
Be sure you’re connected to the internet. Also, your browser may not support WebGL. To test that, visit http://get.webgl.org. If that site shows that WebGL is not supported, then follow the link there to your browser’s support page to see how you might enable it.
This message occurs when the server holding an image or other resource does not implement CORS (Cross-Origin Resource Sharing). The solution is for the server owner to enable CORS on that server. For Apache servers, the article at http://enable-cors.org/server_apache.html explains how to enable CORS.