@IDA_ML: Browser in use? Name/version ...
I am on Win7x64 Ultimate and use Mozilla Firefox with automatic updates. So, I am on the latest version now. This problem I have had for months now. I cannot see a single embedded video on this forum unless there is a link to it. When I browse the net, I can watch all videos without problems. So, it is not FlashPlayer either. On this computer I have only Windows Defender running, no antivirus software installed.
Open the console with F12 and you'll get the source.
There you'll find the link if you search for "YouTube" or "vimeo" 
Thanks Myown,
Here is what I get when I press F12:
Blocked loading mixed active content "
http://player.vimeo.com/video/239736130"
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I have a suggestion to Admin. Since too many people experience the same problem with embedded video as I do and just like me, they don't know about F12, please post somewhere a message to all users that plan to post their videos on this forum that they should also provide a link to the video. Thanks.