I suspect you are working in a Perspective view.
In a parallel projection view, the viewport target is pushed forward along with the viewport camera.
In a perspective projection viewport, the camera moved to the target. When you get too close, you run out of room.
If you press and hold Alt when wheel Zooming in a Perspective projection viewport, the target is pushed along ahead with the camera so you don’t run out of Zoom room.
You can zoom right on through the object.
It might be instructive to turn on the display of the viewport camera in the Perspective view so you can see the frustum and how wheel zooming works.
Camera command, Sho option in the Perspective viewport.