Science videos won’t load

In science, I have been trying to play and watch videos, and only in science, the videos lead to errors, won’t play, or won’t load. I have been wondering if it’s WI-FI that was wrong, but every other lesson videos play perfectly. Say it is scale of the earth and sun which is what I’m watching, and it’s done loading, and it won’t play, or it won’t load, or there’s an error. Please look at the videos.