So...apparently I can play this in my normal browser since the webm is already in my cache, but I can't play it in incognito, even though this is externally linked. I've also seen this issue in other people's posts as well (non-working webm). Is it an issue on the OH server side or elsewhere?
Edit: if I copy the webm link, and open it in another tab, it works. Then if I refresh the page with this post, the webm also works. But it won't work straight off the bat. It's almost as if the webm insert gives up on loading way too soon.