WPMUDEV training video plugin used to work -- now doesn't! Access Denied

The integrated video tutorials were displayed on pages. . . these come up with a completely black screen. I deactivated plugin and then reactivated it -- no change. Then I unregistered my domain at the video API page and re-registered it. No change.
Then I tried adding videos to the HELP dropdown in the Dashboard, and get "Access Denied. Please check site registration."

These videos used to show up just fine on pages.

I can give you access to my site if needed.