When I choose the "share" button on youtbe, this is the link information that comes up that I copy(minus the quotation marks. I had to put those around it so that it wouldn't post the video. So I learned that I don't even need to use the tool bar):
"https://youtu.be/SlPhMPnQ58k"
Do you see the difference between what you are copying and what I copied in the link info?
When I paste that in the "Insert video" button on the tool bar here, this is what happens:
You/we need to figure out why you get a different address. Maybe upgrade your Youtube?
Your song made me cry BTW.