Try to use mp4, this is more common.

But there is a lot changed sinds v11.

The video probably don't show because user has no driver for the format for video installed for some browsers.

So other users might see it correct.

But again I would recomend to try mp4 if possible.

check here for more info: http://www.webmfiles.org/how-to-play-webm-files/

Best Regards,

Andre

No usefull. I tried mp4 file- it didn't work in IE11 the same. Video mp4 stop work in Mozilla Firefox- ask to install media player plugin. Link conduct to microsoft site- it say support the main components of windows stopped 10 of january 2017.
https://support.microsoft.com/ru-ru/help/17777/downloads-for-windows
I don't understand- I put video on site maded WebsiteX5- the first in the world?

Hello Sergey

Be sure the mp4 file is H264 encoded.

This will function in nearly all browsers.

Kind regards

John S.

Thanks! You are the great!