So I played around with SMTube 20.1 a bit further and had a look at the support forum.
Basically what happened was that the author was using the Youtube API to populate tonvid.com.
However his Developer key got suspended due to which he had to use a free key which resulted in tonvid having a lower
bandwith to populate the Youtube URLs.
This is what we perceive as the No URL found for this video in SMTube 20.1.
The author decided to pull the plug on populating Tonvid with the usable Youtube URL's and as such has now removed the Youtube API completely from SMTube, it now has to rely on youtube-dl to first download the video which is then played back by your chose videoplayer. (SMTube 20.6).
Long story short, the one-click directly streaming from Youtube application that SMTube once was, no longer is ...
Has anybody tried the new 20.6 version linked above this post ?
(also noticed you will have to add /Users/<yourusername>/bin to your PATH variable)