sometimes when you put the entire link in the pop out embed prompt, it will extract the wrong unique code for the video. for that link the unique identifier for the video are the characters that starts after "v=" and ends before "&".
all you need to do if your video shows up a white box is just to copy the video's unique ID and post in the youtube prompt
So I just put your code into the youtube prompt thing and to make it work, I took out the s that was at the end of httpS. This was your code: httpS://www.youtube.com/watch?v=PVMqG5n6oo8. If you try to post another youtube video and the code has httpS in it, delete the S. I don't know why it does that or what effect the S has on it working or not, but yeah. Hope this helped.
So I just put your code into the youtube prompt thing and to make it work, I took out the s that was at the end of httpS. This was your code: httpS://www.youtube.com/watch?v=PVMqG5n6oo8. If you try to post another youtube video and the code has httpS in it, delete the S. I don't know why it does that or what effect the S has on it working or not, but yeah. Hope this helped.