That does happen. You need to work out what time the offers re-set depending where you are.

In the UK it doesnt let you watch the videos until midnight, then it runs through to around 4/5AM (or you get locked out).

At the moment I am getting the no videos to watch prompt, but come Midnight it will work again for a few hours - which is long enough to either earn your full 50 Token allowence or see you locked out for a while.