Often times if a video won't play it is due to a slow internet connection.
We can remedy the buffering issue by lowering the quality of the video to allow for faster loading.
In the bottom right corner of the video player, you'll see a settings gear.
Click on that and you will see a 'Quality' option, this will bring up a list of options to choose from.
The lower the number the lower the quality, but the videos will load faster if you're having trouble with the internet speed!