Hello You did find the right vanishing point. You just fall for the brain wanting to display all sides. Here the left side is practically invisible since the side is nearly above at the vanishing point. (your left side follow the orange vanishing line and not the green) You are not alone in this :)
Ah, so that left side is invisible due to the placement of the vanishing point? I thought so, but the drawing solution had the left side drawn as I have in the picture, hence why I drew it once I saw the solution. It didn't make sense that I could see that side, though, because of the position of the vanishing point.

