I see what your error is. If you check your webserver logs you will find a bunch of 406 errros. Web servers expect a useragent and other header info to be passed from the web client when a request is made. The Roku servers use http as a transport but don't pass the all header info so the server becomes suspicious and doesn't send.
Your URL can't be HTTPS either.
You may need to disable ModSecurity in your Apache setup on your WebHost to get past the errors. The following thread discusses all of these issues a little more clearly.