When I try to replicate what happens at 8:18 in the video, this happens. I've merged all vertices by distance.
HI Mohammed rrandomGhR ,
It looks like you still have some 'double Vertices' left. I'm not sure how exactly you managed this, I can't reproduce it..maybe it's beginner's luck.
But anyway, I am pretty sure, that it is because of some double Vertices and if not, there still is something wrong with your Mesh; I just can't tell from the screenshot, what exactly is wrong with it.
