If a video that your TED-Ed lesson is based on has either been removed from YouTube, been marked as private by its uploader, or had embedding disabled, then we are no longer able to display that video on ed.ted.com. In any of these cases, you’ll see an error message in the YouTube video player indicating why the video is not available.
If this happens to one of your lessons, or if you just want to switch the video, you can add a new video to your lesson! Find the lesson you want to edit on your lesson activity page and click into the editor. In the editor, click the "Change video" link under the video thumbnail to update your video. You'll need to paste in the URL for your new video, so copy and paste the URL from YouTube!