Thread:Support/About Wikia:Videohandler-error-video-no-exist/en/reply

Most video sharing services have a functionality called embedding. A user who whishes to have a certain video displayed somewhere grabs a special piece of HTML code from the site and paste it into his code. Pick any YouTube video, click "Share" and then "Embed".

The message is returned when the special HTML code is requested for non-existing video.