Altenative titles for this post could be:
Microsoft Internet Explorer or Edge does not play videos
Microsoft Internet Explorer or Edge does not play YouTube videos
Facts but not necessarly correlated:
Using Google Chrome I was able to play video on Facebook but not using Internet Explorer.
Assumption:
Have you installed Windows 10 N or KN? If yes continue reading this post.
Cause:
“N editions of Windows include the same functionality as other editions of Windows, except for media-related technologies, Windows Media Player, and certain preinstalled media apps (Groove, Movies & TV, Voice Recorder, and Skype). Media Feature Package provides a way for a customer to restore these excluded technologies. Some features will require reinstalling hardware drivers after installing the Media Feature Pack.”
Solution:
- Press Windows+X then select System to find (under “Windows specifications”) which Window Edition and Version you have installed.
- Open the following link:
https://support.microsoft.com/en-us/help/3145500/media-feature-pack-list-for-windows-n-editions - Download and install the Media Feature Pack corresponding to your version (a system restart is required at the end of the installation).
Did my solution solve your problem? Leave a reply.
on the browser toolbar then select Settings, click on Extensions and 
Remove from Chrome at the line of the extension Business Flash Player !