YouTube have changed the way they link to videos recently and it has been causing some problems so here is a guide.
You can no longer just copy and paste the link from the top of the browser as on most browsers this will result in an error page being displayed.
You need to click on the "Share
" icon just below the displayed video, this will open up a box just below it with a link
that usually reads https://youtu/be/xxxxxx
Copy this link into your post
If you post the link as is, you will have a an active link to the video, if you want to embed the video into the page so it displays a picture of the video then after you paste the link and before you hit post remove the "s" from "https://youtu.be/xxxxxx
See below for more info.