The YT preview doesn’t seem to work for this video.
It works now, it seems that not removing the query part of youtube list/playlist was the fault.
The playlist was simply made private.
&list=LL&index=11
Original (Playlist was private/hidden, so the preview did not work)
https://www.youtube.com/watch?v=81rBzfbFLiE&list=LL&index=11
Removed from playback list. (works as expected, as it is not inside private playlist)
https://www.youtube.com/watch?v=81rBzfbFLiE