Christine and Mark, please clear your web browser cache.
If you have any sort of temporary network issue that results in the video being 'unloadable' (black screen) then subsequently every time you go to view the video, it will give you the same issue (corrupted 'empty' video is cached by your web-browser, and it doesn't attempt to reload it even though the internet connection is OK now.) - until you manually clear your browser cache. (Some browsers purge the cache from time to time, others do not...)
This is a known limitation in the browser's video player, but the workaround is to clear your browser cache - and then that video will become visible again (the browser will go out and download it, rather than reading the 'blank' copy cached on your hard drive...)
Part of the oddity of this is that our main website is located on the west coast, but our video server is currently located on the east coast, and so while you may have a perfectly clear path to our web page encapsulating the video, its possible that there could be a blockage between you and the video server on the other coast. It's really only 40 milliseconds difference, but some days the internet routing gets so wacky that your local connection can literally take the long way around (20 hops the other way across the planet). Internet routing works perfectly 99.9999% of the time - but once in a while, regions of the internet can be isolated from other regions, when a crucial switch somewhere goes into a loop.
