[Studio25]

When someone posts a video on YouTube, it allows them to decline to allow the video to be shown on mobiles, to be embedded on other sites, to be voted on, to be commented on, etc.

The person who put the post on the forum has simply not checked whether the embedded playing function has been disabled before posting.

The simplest way to do it is to preview your posts and try to watch the video. If you can't, then change the post so it's a link away from the site to youtube.