YouTube "Safety Mode"
If you use the Chrome browser, you may have been getting this message lately when trying to view YouTube videos.
To disable "Safety Mode", scroll to the bottom of the page and click the drop down next to "Safety". Select Off and click Save. Refresh the video page and your video should begin to play.
If you're trying to view a video that's embedded in another webpage, go to https://www.youtube.com. Follow the instructions above and then return to the webpage with the embedded video.
For more information about Safety Mode: