Check the address bar of your browser for security warnings. Click on the warning and allow unsafe content.
If you see a black or white screen instead of the video, try disabling hardware acceleration. Here's how to do this in different browsers.
Click the icon with the three horizontal lines or dots in the top right corner of the window and choose Settings.
Scroll down and click Show advanced settings.
Scroll down and remove the check mark at Use hardware acceleration when available.
Follow the steps in this video: https://www.youtube.com/watch?v=ueb9DWJDjNg.
Follow the steps on https://support.microsoft.com/en-gb/kb/2528233.
If you use an internet filter or proxy server, this could cause problems with playing videos. Change your filter settings and put the following domains on the whitelist:
If you don't know what to do, please contact your filter provider.