There will be a brief loading bar and then a blank page. And then a next video button at the bottom.

There's nothing about videos being unavailable. They just don't show up.

If you have ad block enabled they do not show up sometimes.

Ah, that's probably it. Thanks :)

Did you check to see if that was the case?

Yes I did and it was the case.

Lock please?

Of course! Glad you got it figured out!