The most likely cause of constant buffering is a slow or fluctuating connection speed.
We recommend a connection with a consistent speed of 1.5Mbps for our videos. You can check your connection speed at http://www.speedtest.net. Please be aware that some ISPs (Internet Service Providers) perform better in the test than in real world scenarios.
To improve your network performance, close all other downloads and check that software on your computer (like Windows or your virus guard) isn’t currently being updated.
If you continue to have problems, we recommend you contact your ISP.